Did I mess up?

I (26m) ‘ve been seeing a girl(26f) for months. We broke up once and after a couple months started seeing each other as a friend. I’ve never stopped thinking about her and my initial thought when I started seeing her again as a friend was just to be close to her even without any relationship. I didn’t want to lose her. Things went well and we got closer and closer. I had feelings for her but couldn’t tell her, cause I was too scared to freak out and lose her. Last night she told me that she’s been thinking about me too and wants to be in a relationship with me but she needs to take it slowly and I completely agree with her. Then I started to express my feelings about her. She told me that she loves me but I couldn’t say it back to her even though I fuckin love her. That happened in my car, after that we went to my place, had dinner and watched 2 movies, at some point I felt she wanted to be closer to me, maybe a huge or kiss but I didn’t do anything. She doesn’t talk too much. I’m just guessing but couldn’t think about that I’m a shy piss of shit person that let the girl of his dreams down. I’ve never been in a serious relationship and I don’t know when it is the right time to do things like the first kiss. I overthink everything. Im Always thinking about whether she wants it too or not, and in the end I don’t do anything. I feel awful