Should I ask her?

[mildoxymoron]

Long story suuuper short, just finished my first year of college and 'rona has me alone and reminiscing. Thinking about this girl I crushed on all of high school, on and off. We're pretty good friends, but I wouldn't want to ruin that. She took a gap year and is going to an all-girls college over 1200 miles from me (since my school is 1200 miles from home and hers is the other direction quite a bit) starting this fall. I find myself wanting to ask her what might have been in high school, partially so I can stop thinking about it and partially with the high hope for the miniscule chance that she responds saying she's crushed on me for a while too and wants to try something long distance meeting up over breaks. I have a document written out explaining everything, and even though at the time I had little to no intention of sending it, I'm getting tired of not knowing. Is it worth risking the friendship for answers and the tiny possibility that my High Hope™ from earlier happens?

[FMW]

Start on a smaller scale, don't send the "document".  It was a good way for you to help organize your thoughts, but would likely be overwhelming to her, especially coming out of the blue.  It might scare her off, even if she had been interested in you in high school.  

Are you in regular communication right now?  If so, start easing into the topic, something like "hey I miss seeing you, when do you think we can get together in person?".  Her reaction to that suggestion, her level of enthusiasm for it, will tell you if you have at least the possibility of her returning your feelings.  If you're not in regular communication then you'll need to start by opening the communication back up with a "Hi, how are things going?

1200 miles is quite a distance apart.  It's hard enough to maintain an established, on-going relationship with that distance.  Starting something new (even if based on a previous relationship) would be almost impossible if there is no end date to that distance in the foreseeable future.   

The lack of other options given the current COVID situation probably has a lot more to do with your current focus on her than any actual meaningful connection with her. 

[mildoxymoron]

@FMW We're already in regular communication, have been ever since we graduated. We're pretty good friends I'd say; a lot of our communication is just memes but we check on each other, and even though we've only hung out one-on-one once that's more than I can say for most of my high school friends. (We sort of hung out in classes every day, too, tbh. We made it fun for ourselves between the two of us.) That one time we hung out she seemed pretty enthusiastic to see me and we had a ton of fun, content was pretty close to a date looking back. But I'm not one to say "that was definitely a date, she likes me", nor am I one to take things out of context. So far, we're just friends, so when we hung out I took it as such and just had a great time that way. So the thing is, I'm back in my college town for the summer doing an internship, so I won't be home until this December, and that's not even a guarantee.

I left this out of the original post on purpose (tried asking for advice with all the context before and wasn't exactly satisfied so I figured I'd see if simplifying it would have more people relating to it), but as to your final point I wouldn't say there's necessarily a lack of meaningful connection. We both skipped the same amount of grades, which is rare to find, let alone more than one at a school, and with many years' experience dealing with that social gap I can say having her around was super relieving, and she's said the same to/about me. We kind of held each other together a lot of high school, especially the last two years. That also kind of goes to the point of not having other options due to COVID: I don't really ever have options anyway. The idea of dating people older than me stresses me out, and I can't really wait a couple years for people my age to enter my school because then if I start something serious I leave the school/area a couple years before they would. I can easily pass for the correct age for my college year, and people don't really look at me and think "he's younger than me" anyway, but I'm not the type to deceive people, especially about something that integral to my identity, and especially those who I want to get to trust me.

But anyway, the only reason I'm so disproportionately scared to tell her how I feel is because I feel like it puts the friendship on the line. Even though I don't think she'd be one to just throw someone away like that, I tend to overthink things and worry about the least-likely-most-destructive scenarios, so here I am. I don't consider there to be much of a chance that she'd want to try something long distance, but I do consider there to at least be a chance at all. Mainly what I want is one of two options: first, stop thinking about her so much, or second, have all that thinking not be in vain.