question about finger position..

is it ok to play any finger in the key as long as you're comfortable with it?? im sorry for my english.. please help!!.. ^^..

Well, sort of. The best thing to do is to try to make it as easy as possible!
In the beginning almost nothing is comfortable, so I would actually suggest to try to do things that might not feel comfortable right away, but which you can tell is easiest!! If you understand what I mean by that?

Ex: Like using the 4th and 5th finger is the easiest move in a piece, but its maybe very uncomfortable in the beginning, but after some practice it suddenly feels comfortable after all!

But its all comes down to what you can do and not ect, so if it feels right, it might be hehe

ahhh.. it should be the most easiest to move.. ok get it.. thanks thomandy!

You're thinking about it the right way. Your hands need to be able to follow on/press the next key as easily as possible as thomandy said.

It's good practice to number your notes with the appropriate finger (1 being the thumb and 5 being the little finger). So while you're reading the notes you can also see or just refer to the finger you are supposed to press to get the best result.

ahhh.. ok.. THANKS!!

Thats such an awesome idea about numbering the notes on the music sheet! Initially all the notes then eventually just the hard parts. I've noticed on some sheet music where there is peculiar fingering that there are tiny numbers underneath the staff to indicate which fingers to use