My ex and I dated a little under a year ago for 8 months when I was 16 and she was 17. We're now 18 and 19. I moved across the province when I was 17 after the passing of my mother and I met my now ex at my new high school. I was a lonely tenth grader and she was a popular 11th grader who took interest in me so I kind of went into it without a second thought. She suffered from various mental health issues that eventually lead to me breaking up with her, I feel bad about it but it really took a toll on me and I was more of a therapist than a girlfriend. She refused to look after herself and caused me incredible amounts of stress, so I left. We ended on amicable terms, but that soured when she repeatedly made unwanted contact with me months and eventually over a year after we split. She's made it incredibly clear she wants me back and I want absolutely nothing to do with her.
The girl I'm currently interested in and I are in our senior year of high school and my ex is in her freshman year of uni. The new girl and I were fast friends as soon as I moved, and her and my ex only became friends after we broke up. Frankly, I'm not even sure she knows we ever dated. I never had eyes for her while my ex and I were together but a couple months after we broke up I started having feelings for her, and It's been over a year and a half since my ex and I broke up and a year since I completely cut contact with her. Personally I feel that's a very respectably amount of time. I'm sure this girl is into me and I really like her, I just don't know if I should make a move.
I've talked to a couple other people and gotten mixed opinions, so I've turned to the internet. I know it's frowned upon to date your ex's friend but I feel like this situation is kind of different. Thank you for hearing out my petty teen drama.
TL;DR: My ex, whom I broke up with about 2 years ago and isn't the most mentally stable or kind person, is friends with the girl I want to pursue romantically. Her and my ex only became friends after we broke up, and while they text multiple times a week they are no where near as close as I am with her.