HANG ON. HANG ON. HANG ON. There is so much better of a way to approach things!!
Firstly, grab the facial washer thingy, & the condom stuffed with playdough. Next, go out, buy a proper vibrator. Then sit your daughter down for a 'talk'. Tell her, and explain WHY & HOW those things could be bad for her. (I'll put it simply; Imagine if the condom breaks. That's one hell of an embarrassing trip to the doctors. Not to mention, imagine the infections she could get from the face cleaner. Once again, an embarrassing trip to a doctors to get antibiotics for her infection.) Give her the vibrator, under the condition she cleans it properly with warm water & soap once in awhile.
You're probably asking yourself 'Isnt that encouraging her?' and I'm sure some people could argue that it is encouraging her, but let's face it; Better to know what she's doing, and that she's doing it safely, then let her mess around with **** that could be bad for her, or scold her for something the average teenager gets into.
Next, have a nice day out with her. Go get your nails done, or your hair, or go to a spa, or just go get a nice lunch. Just you two. BOND. At some point, bring up guys CASUALLY. I will promise you this; you ground her & say 'DONT DATE', she will cling to the person she's dating even more or want a relationship more.
Ask her why she didn't choose someone her own age. Ask her if next time if she'd mind trying someone closer to her age, as it might last longer, and the person might have more in common with her. Instead of being upset she went for someone 18.
Saying 'No' only urges her on. Instead, let it be known you're okay with her dating, but you want her to talk to you about it. If she wants to be with a guy, he has to be introduced to you. If she wants to go on dates, you get to drive her there & back the first few times. Set some kind, but fair ground rules for dating.
Make relationships & physical things, something you both are comfortable talking about.
Next, lets be honest, average girls lose their virginity between the ages of 14-24. It happens. You probably did too. So talk to her, casually, as her FRIEND, don't scold her for wanting to try things. Just make sure she knows to respect herself, don't get pressured into things she doesn't want. Teach her to know her own boundaries & how to respect herself. Make it known that when she feels she's ready to become physical in a relationship, that you're ready to listen with an open mind.
Realize this; It's better if she has sex on her bed, at home, with condoms you gave her, with the boyfriend you've met, than in some creepy guys basement, the one who you said she couldn't date, the one you've only ever seen a photo of, with no protection, where she gets pressured into more than she's ready for.
Next; Computer history can be cleaned out. There are ways to remove specific sites from history, and even ways to set things up so no history gets recorded. Teens grew up in a technical age. They know what they're doing computer-wise a lot more than you probably do.
Lastly, focus on her dishonesty. Ask her why she lied. Did she figure you wouldn't let her go there, especially if boys were going? Find out WHY she's lying and make a deal with her. If she wants to go to say target and hang out with some friends and a couple of boys, remind her of the penaltys of shop lifting, explain the concept of 'accessory', that even the 'nice' friends can sometimes shop lift, that she should know not everyones always honest, and that if they steal, she'll go down with them. Then drop her off at target. If after target she wants to go to the movies with them, and walk there or catch transit with them, let her go.
I figure you're thinking 'What if she lies again?!' The best solution; Check in on her occasionally. Tell her every so often you're going to meet her at a check point, so you KNOW shes where she says she is. Tell her that the more she is where she says, with the people she says she's with, the less check points there will be. Let her know you're okay with her hanging out with a few friends and a few boys, out in public, as long as she's honest. If she breaks check points, up the # of check points, or lower the # of times she's allowed out in a week.
You need to focus on building an honest relationship. You may not always like what she has to say, but if you learn to be open minded, realize she's young and looking for a little freedom, and help her to find it in a way you can both live with, you'll quickly find the house is a more pleasant place, and your daughter, is a lot happier to come to you. It may take weeks, but it'll probably take months, if not over a year.
Your business of snooping, & not saying anything to her? That's all building more distrust. You just grounding her cause she lied; more distrust. You are just building on this distrust, which will only make **** worse. You need to build a trusting, open, relationship. Open confrontation? Won't help. Having open ended conversations, where you keep an open mind, will. Asking questions rather than using accusations, gets BOTH of you talking. Not you screaming, and her storming off to her room.
Unfortunately, if you lock her up in her room, for her entire teenage years, and deny her the ability to socially experiment, you'll quickly find that the moment she has freedom, she'll over-go on it. She'll be that 19 year old woman, up on a table, drunk out of her mind, stoned, and completely naked infront of a bunch of guys at a strip-poker match that got outta hand in some 28 year olds basement, who ends up pregnant and with an std before the nights up.
However let her have a bit of freedom, while teaching her how to have it responsibly, teach her that she can come to you without being scolded for everything, and you might just find you have the ability to have a beautiful relationship with her.