Good luck in your flight training. Keep at it.
It's a good thing that you may feel dissapointed with your progress at times, becasue it will make to want to learn even more. Don't get disheartened. You'll have plenty of good days and bad days.
Don't worry what the other student pilots are up to. Who cares if they go solo after 10 hours? If it takes you 20 hours to go solo, then so be it. The feeling that you've really worked for it will make it the more rewarding!
Happy landings,
Tiggermoth