introducing myself

Hi,

I'm Sophie from Hungary. I'm I've become the a member of this page site because I would like to practice my English. I'm I've been studying this language it from the since a very young age of mine, but I still have still a lot of things to learn.

You can also say, I've been studying it for ages, for a very long time, since I was very young,  

the phrase you were probably thinking about is:   "from a very young age", You can't use it with present perfect though. 
" a lot of things"  is ok,   but   " of things"  is redundant and unnecessary.

Hi,

I'm Sophie from Hungary. I've become the an italki's member of this page because I would like to practice my English. I've been studying this language from the very young age of mine since I was very young, but I still have still a lot of things to learn.