Please help

I, a 16(m) year old thats never been in a for sure relationship, doesnt know what to do at all.

So some girl who doesn't go to the same school as me was trying to get with me and Im 100% sure still is, but I'm not sure if I'm fully into her. She looks and acts nice but is just too much I think. When we are talking she would bring up how she smokes and drinks lot and I'm just really not into stuff like that. I don't know if I should still try and talk to her or just be friendly.

Then, there's a girl (goes to same school) who Im sure is into me but I'm not for certain. She's really nice and doesn't do any of that stuff. I still don't know much about her but she looks to be a really good person. I want to start talking to her but I don't know where to start even though we dm'ed before.

There's another girl (goes to same school) who I'm really into but I only know a bit about her personality and it seems pretty good. She's really popular and pretty so I don't know if I'd have a chance. I never have the right time to talk to her because the class is rushed all the time. I've only talked to here about three times. The real problem is she close friends with the first girl and I'm not sure if that just means I can't try at all despite really wanting to.

I dont want to be talking to multiple people at once and it's getting a bit stressful if I should do something. And my bad if this is confusing or cringe but I'm just beyond confused and need help from someone from the outside. If you want more context about anything just let me know. Thanks.