Well it depends,

but i heard the the depth is 8 inches and the g spot is only 2-3 inches deep or something like that =s, anyway basically as long as its 3 inches you should be able to satisfy her.

Im sure all men probably worry about this but dont worry its normal as long as its not like 1cm small you should be ok

Remember its not about the size of your dick its about how you use it.