I(22M) don’t know why I’m feeling this way about this girl (21F)

r/

I (22M) met this girl (22F) online almost a month ago. And we hit it of really fast. We liked each other and we have been talking none stop everyday since we met. And she’s a really nice girl that looks forward to her future. She’s and extrovert and she talks a lot but I don’t mind it that much. And considering I has been almost a year since I got to meet someone new she was really nice.
Yesterday we met for the first time. I took her to my favorite park and we has really nice time. We even kissed, and even though she was shy about it, it was nice. The conversation was flowing really nice and everything seemed to be going well but I have been running to an issue and it happened while we were at our date.

The issue it that I can’t seem to stop thinking about my ex (22F). For context I only dated my ex for 5 months and we broke up around 10 months ago. The break was clean and there no fighting or anything she just couldn’t handle a relationship at the time and even though I tried my best to make it last she made her decision and we ended things.

So back to our date I keep thinking about my ex and I feel so bummed out that my ex is so much better than this girl, I mean emotional speaking and how she was as a person. And the thing is even though I like this girl I don’t like her as much as my ex so my mind keeps telling to end it while it’s early but I don’t want to hurt her because she has been so much pain in her past, so can you help me decide what to do.

TL; DR; I met a girl only after almost a year of being single and I met her in person and even though we liked each other a lot I couldn’t stop myself from think about my ex and that feeling doesn’t seem to go away so what shall I do.