I would like to say, it is entirely feasible to learn something at the age of 65. Some people over 60 around me are learning singing, dancing or painting. I admire them. Age should not be a roadblock in front of you that prevents you from learning something. {I believe there is no one but has a dream, out of some reasons, you have no chances to learn a certain skill when you were young till you get old, or you just start to take interest in that thing at the age of 65, so why should not we give ourselves a chance to try it.} I believe there is no one out there who does not have a dream. Perhaps you did not have a chance to learn a certain skill when you were young. Or maybe you only just started to take an interest in a certain activity at the age of 65. So why should we not give ourselves a chance to try it. Additionally, the upsides of learning something when you are above 65 are abound. First, it is definitely helpful to maintain your mental health. Your brain receives a bunch of positive stimuli when you are learning something new, which keeps you energetic(keeps you lively and alert). It is said that seniors who keep learning have lower risk of having diseases (such as dementia). Plus, you will be happier. The sense of achievement you get from learning is worth than a lot of money. And then you will be more confident. All in all, everyone has his own time line. Age is never a problem. As long as you can, learn anything you like without hesitation. The sentence in {...} above is way too long. There are too many clauses so it is very hard to construct it in one sentence. It is also difficult for the reader to grasp it. Below it I wrote what I think you wanted to express. I do suggest avoiding these long sentences in future as everything else you wrote very well, there are only very few mistakes.

I would like to say it is entirely feasible to learn something at the age of 65. Some people over 60 around me are learning singing, dancing or painting. I admire them. Age should not be a roadblock that prevents you from learning something. I believe there is no one who doesn’t have a dream, for some reasons, they have no chance to learn a certain skill when they were young. When they get old they start to take interest in that at the age of 65,so why shouldn’t not they give them self a chance to try it. Additionally, the upside of learning something when you are above 65 are many. Firstly it is definitely helpful to maintain one’s mental health. The brain receives a bunch of positive stimuli when learning something new, which keeps one energetic. It is said that seniors who keep learning have lower risk of having diseases. Plus, one will be happier. The sense of achievement acquired from learning is worth more than a lot of money. And one becomes more confident. All in all, everyone has his own time line. Age is never a problem. As long as possible, one should learn anything fancied without hesitation.