I just gotta say... no offense intended towards your GF.. but what the HELL was she thinkin? Even tellin you that.. sorry.. but in my own opinion.. some things are better left untold.. comparison to an ex is one such thing.

Secondly... not the quantity that is important.. it is the quality.. not to say that with EXTREME differences (I don't consider an inch extreme) there might be sensational differences, but usually such differences can be compensated by experience and technique.

Just my opinion.. but if she tells you that she is happy with the way things are.. then believe her.