I matched with the girl I had a crush on in high school and don’t know what to do.

So about a month ago I (21M) was on tinder and stumbled across the girl (20f) I had a crush on in high school. I was swiping and happened upon her profile. I obviously swiped right because I still think she’s cute and about an hour later, to my surprise she liked me back. I was at work so I wasn’t able to send a message immediately. I sent one that night when I got off. Well coincidentally the next day she went on a month long vacation with her family. She just got back and I’m wondering if I should message her on Instagram since we both follow each other. I think it should be fine since we had classes together and were in the same clubs but I’m not sure. Would it be smart to send a separate message on Instagram or just leave it to tinder.

Tl;dr: Can I message a girl from tinder on Instagram if we know each other from Highschool and follow each other