If i start doing that will i learn some other things?Will i improve my skills?Or i i will spend my time?(sorry if my english is bad)
First of all, your English is fine, don’t worry about it.
Should you do the legacy stuff? You won’t learn anything different, I don’t think. I would say if you feel completely lost (more than the normal amount of lost a programming learner feels) then you could do it for a refresher. Personally, I think it is better to keep moving forward - people can get trapped by worrying too much about how well they are learning things. This is a lot of stuff and it is very confusing when you are learning it.