I might be over thinking this but do things still seem alright?

Over the summer I started talking to this girl and we went on a few dates. The last date happened the night before I went off to college. That date consisted of getting a hotel room, swimming, talking, and having sex. The next day we held hands on the drive home and I dropped her off at her place then drove the 2-3 hours to my school.
A couple weeks after I moved up there she started to get a little distant. I know she’s getting stressed out over work but it’s other things too. She used to be really flirty, and use a lot of emojis in her messages now not nearly as much. She used to screenshot a lot of my jokes and more romantic things I’d say to her and again she rarely does it. It’ll also take her double the amount of time to reply where she once told me she likes to reply to her close people in two hours or less and she used to.
Don’t get me wrong she’s still flirty and giggly. A few weeks ago a friend said they saw her on tinder. She didn’t have any bikini pics or anything suggestive but she was still on there. Since then things have gotten a little better between us. She laughs a little more, she seems flirty, she acts kind of like her old self. We’ve talked a little about plans for dates when I get home.
I get we’re not dating so she can go on dates and see other people if she likes but I don’t want to fall for someone who doesn’t feel the same way. Just right after our last date she said she wanted to be with me but she just broke up with her ex so she wanted a little time first. I was planning a special date where I’d ask her to be my girlfriend over winter break but wanted to see what you all thought of the situation.