Hi
sounds like you are doing fine to me. When I started playing I was in my teens and would practice for hours on end. Although I now play a lot,(I am 52) I practice from time to time, but know I would not have the tenacity to practice more than an hour or so at a time. I sometimes give guitar workshops and see how frustrating it can be for people to pick stuff up. I would say keep at it. Practice tunes very slowly but keep the rhythm going. Only speed up after you can play a tune slowly and precisely.

Good luck
Ashley
www.rag-mama-rag.com