@Crazielady420,
The decision about whether to have another kid was almost harder than the decision to have a kid in the first place, for me. I always knew I wanted to be a mom, but once that happened, I just wasn't sure of the right number. Some of the things I took into account:
1.) How was pregnancy and childbirth the first time? (For me, about half of pregnancy was great, half was horrible, and childbirth was incredibly awful.)
2.) How well are you able to balance attention to yourself, your significant other, and your existing child(ren) right now? My husband works a LOT -- like 80-hour weeks -- and that had an impact on my decision.
3.) What are the personalities of the children you already have like? My kid was always "high needs" -- happy and friendly but really in need of stimulation and attention. My mother-in-law tells me that my husband was the same way, and they're both (husband, daughter) very smart. I don't think he was actually well-served by having siblings (he's the oldest).
4.) When you look 20, 25, 40 years in the future, what sort of family do you see? What do you think would make you happiest/ what would make you sad if you don't have it?
5.) How strong is your current relationship with your significant other? A new baby pretty much always puts a lot of strain on things.
6.) What is the minimum age difference between your current youngest and the possible new baby, and how does that affect your life? For example, if you currently have a 3-year-old, the next one would be about four years younger. That's an extra four years until they're all in school, an extra four years before they're all in college, etc. How does that affect your life plans?
7.) What's your money situation? Obviously anybody can have a kid, and money shouldn't be the only consideration. But it is definitely a consideration, especially if money is tight (kids are expensive.)
and in your situation, since you can't choose gender:
8.) If you're trying for a boy and have another girl, how does that affect things?
I ended up deciding to have only one. She loves babies and toddlers and is a great babysitter but says she's very happy to be an only child. I'm an only child and was happy with that (though I'm certainly not loving that all the responsibility falls on me as my parents get older -- but even then I know that in some families, the adult siblings can be more stressful than helpful).
Good luck with your decision.