What can and should I do?

So, I posted yesterday about messaging an ex who broke up with me before we graduated high school, and I found out why and wanted to apologize, and she hasn't read it on Facebook yet, and it's been months.
So I sent her a DM on Instagram, and she hasn't read it either, and her last post was 6 months ago... What should I do?

This is what I sent her:

Hey, sorry to bug you, but I sent a message to you on Facebook trying to apologize for what happened when we were in high school. I'm sorry I lied to you, and I'm sorry for all the stupid things I did. I can't say I was young and dumb, because I knew how dumb I was. I should have never asked you out when I didn't have a phone and had the restrictions from my parents. I handled everything between us in high school wrong, and I deeply apologize. I don't mean to pester or annoy you, like I Have In the past, but I just felt like I needed to apologize, I know it may not mean much. But I'm sorry.

Also, thoughts on the message?
What can and should I do?
Add Opinion