I think a girl I’ve known for years through my small knit video game circle could be interested in me

TLDR there’s a girl I play games with who I’m 70% sure is (or was) interested in me but our communication is finnicky and I’m awkward.

I (24M) have a pretty close group of some online friends I’ve been playing video games with on and off since about 2012. In this group of ~7ish people there is a girl (~24F), the sister of another friend. Basically, it’s really hard for me to tell, but I’m fairly sure we’ve been sort of indirectly flirting for quite a while now. I’m really lonely, so perhaps I could be making things up in my head. The thing is, she is typically very reserved when it comes to fairly personal conversations. We’ve all known each other for years and get along really well, but a lot of personal life details don’t get brought up, especially with her. She has sent me (not the only one albeit) letters in the past, and also a really thoughtful gift. She followed my mom on instagram and messaged her about it, and they’ve spoken before. I just generally do get the feeling she is interested in me, but personal messaging between us is few and far between. I definitely can see myself dating her, but I am extremely shy with this stuff. I also feel that I just don’t *really* know enough about her other than what I can gather from the topics of discussion that happen to arise. I don’t want to goof up a really awesome friendship with her as well as her siblings. And also there’s the distance part. We’ve all talked about meeting up together but I also want to know what her feelings are before that would happen? Lastly I just generally have limited dating experience so I really don’t know how to go about it.