I don't see any harm in reaching out to her as a friend. Before you do, though, make sure you have thought it through (with your head, not your heart). Yes, that's easier said than done. But, you need to be prepared - knowing what your hopes & expectations are - and what you'll do if things don't go the way you hope for.

The embers of old flames can burn for a long time. And because they do, they can give you a sense of something you once had that you'd like to build on. But that prior relationship isn't what you want to build a foundation on. Time and circumstances shape who we are. So neither of you are the same people now as you were then.

Reestablishing a solid and genuine friendship, with no expectations of anything else, is where I suggest you start. I don't think it would be fair to either your heart, or hers, otherwise

Good luck, OP.