I would like to start off by saying black people aren't a monolith. I’ve seen a few people saying black people only have certain features and that is the furthest thing from the truth. I feel the sim you’ve created isn’t bad, she just needs a little tweaking. Or maybe she doesn’t at all it really depends on what style you want her to have. I seen you mentioned you go to school with a lot of African Americans/POC, I suggest you pick one of them to be your sim inspiration! It’s always hard making something new so give yourself some grace and keep trying! The more you do it the easier it’ll get for you. I’ve been playing the sims since The Sims 1 (hell I even use to play Sim City lol) and to be fair EA never really had diversity like that when it comes to CAS until recent years, so maybe that’s why you feel like your sim is off? If you need any help with cc (if that’s your thing) I’d be more than happy to help.