I wouldn't worry much. I was the only female child (I have 3 brothers) and although my mom insisted on dressing me with pink-girly stuff I never really felt comfortable in them. I would always complain and use more boyish things. I know my mom was very frustrated with this, but I simply didn't feel well - I felt calling more attention than I should or wanted - and this happened really early! So, as time went by I just grew up to be a girl! I never respected girly girls as they should be respected, though... I am happily married and have a baby and have no question about my sexual tendencies... :-)
I would really relax and let go.
I hope this helps.