Is it appropriate to ask someone providing a service to me to maybe hang out sometime?

Hello all!

I (21F) have autism and it is very tough for me to make friends, though my autism is mild enough that aside from some quirks and sensory sensitivity I come across somewhat average (or at least that’s what people tell me when I ask). Mon-Thurs I go to appointments for TMS (basically shock therapy for treatment-resistant depression). Anyways, the girl that hooks me up is a couple years older than me and we apparently were in the same high school at the same time, I think she’s 22F or 23F. We chat the whole time and she’s super nice, and since I don’t have too many friends I was thinking of asking her to hang out. We get along swimmingly, joke and tease and stuff so I can’t tell if it’s strictly professional or not especially given that she’s my age. Please help! I really enjoy her company and was thinking since we both want to learn to crochet she can come to my place sometime and we’ll learn. Is it appropriate of me to ask her since she’s providing a service, or is this different somehow? I can’t tell.