@OwenXx,
Don't confess feelings.
Just ask something like -
I really enjoy spending time with you. Would you like to get a soda (or coffee, if you prefer)
this weekend?
That's your script. Don't just toss out a stream of consciousness like "I like you but I'm not really asking you out because I have no idea if you're in a relationship and I'm terrified of being rejected and ...."
You have been hanging around for four months and building this whole thing up, I am sure. If you aren't clear in your intentions, then your crush will just think,
oh, that's nice and things will not have changed one iota.
Please skip this utterly unnecessary step. It's just another way to build things up even more give you more terror and more feelings of awkwardness so that you can wait another four months or more. Plus it gives you a second chance to be rejected.
Get the asking out part out now. Don't hesitate. Seize the day. If your crush in a relationship, then they will tell you. If not, and they are interested, they will be receptive. If they aren't in a relationship, but are still not interested, then I hope they will be kind enough to let you down gently.
No matter what, it will be better than not knowing.
Your note, as it stands (and you're sending it through Instagram, of all places? I hope you realize there's pretty much no privacy there), does not give you the opportunity to either end this mental stalemate or at least get more information.
Make this communication work for you.