I think your sister and girlfriend are giving you excellent critics of you work for free, you should thank them
I like you usually use myself as the test but like you pointed out, you and I are advanced internet users so we are not good test case but our experience will also help us see faults less experienced people can see but I think we should all use at least five users of mix abilities to test our designs for usability, each person will see different faults which in the end makes out application or web design more user friendly.