Hi, for about 3 months i was playing G chord with my pinky on the 3rd fret of the high E string. Then i found out people played it with their ring finger, so i did that for a few months, and it still doesnt feel right... Anyways, does it really matter which finger i use? Will i be screwed later on if i use my pinky? Thanks!
Also, if something is: 3,2,0,0,3,x , can i play that last 3 with my pinky without being screwed over later on?
it wont screw up your pinky... it will probobly help its strength in the long run.
1) Don't double post, use the edit button.

2) It doesn't matter if you use the pinky or the ring finger, it's a matter of preference.

3) That last 3 shouldn't screw you over at all.
<Han> I love Hitler
It doesn't matter how you hold the chord, as long as you sound out all the correct notes.
I def learned that you use your ring finger for the high e string, I find it more comfortable being that its stronger than the pinky. As for your second question Id say you want to have your pinky free in that case because if that e was to be unmuted that third fret would most likely be played and you dont have any fingers after your pinky to get to it. Keep in mind that this these are just my opinions and I am basically self taught, so if you really want to make sure id ask someone who really knows.
I play G 320033, so I use both the ring and pinky while playing it. Of course, sometimes depending on the previous or next chord I will use 320003, but I like the fuller sound of 320033.