Does anyone start messing up the relationship once you start to really LIKE/love them?

Does anyone else get these feelings where once you ACTUALLY start to like/love them you mess it up by overthinking? This happens to me each time, we are just having fun with each other having a great time we semi have feelings for each other. The MOMENT I actually realize I really like/love her and want her as my GF is when things start to mess up. I start thinking/trying too hard to impress her and it kills the relationship dynamics (lost of interest). Does anyone go through this and how do you handle it?