Background: This girl(now 17) confessed of having a crush on me(now 18) 2 years back before the pandemic even started and I politely declined (She was too young and looked very child like at that time).

Now she has started following me on instagram, and we are texting here and there, just light jokes but haven't flirted with her on text. She looks attractive now, I told her to join me and have an evening walk together. Should I flirt with her and try to turn it into something or should I just remain platonic friends?

Edit: I know I have to make a move, maybe I was just not confident in myself and was looking for reassurance here.