Keep at it.
I gave in to the craving in my mid forties and kept at until I passed.
As far as I know It is reflexes and mussels that slow down first: and if you are relying on either for safe flying then you are in the wrong business, If you have average strength and reactions you should have no trouble.
I had a big problem with tuition. When I finally qualified I had 13 instructors in my logbook. I'm not saying any were bad teachers but all had their different ways and that can cause problems. The one who was unavailable because he was arrested for attempted murder was unusual, but you get my drift.
I will bet that you are like most of us trying to get your licence "part time " and coping with the British weather. If you could dedicate 4weeks to intensive training then I think you would have no problems.
There are people how will never have the basic co-ordination to be able to fly safely but I think these are few and far between. As long as you are sure that you do not fall into this category then keep going.
Let us know when you go solo.