No, absolutely no, masturbation does not cause memory problems!!
but my dout is that weather it causes loss of memory disorder because i did the masturbation when i was 7 years ild
It is quite normal for someone of your age to masturbate, and two times per day is certainly quite common.
There is no physical harm or damage that you can do to yourself by masturbating this frequently.
You don't say if you have a sexual partner, or if you are sexually active? My only concern is that, if you become too dependent on masturbation, you may not have so much enthusiasm or energy for sex with a partner. You may end up prefering masturbation to having sex with someone else, which would be a shame (because sex with someone else can be so much better), and may be a difficulty in your relationship.
For now, I would say that you should not worry about how much you masturbate, there is no problem. But when you have a partner who you have regular sex with, it may be a good idea to stop masturbating, or at least reduce it a lot.