How soon can I know the gender of my baby??

G.
So I'm 14 weeks 5 days pregnant and I really want to know if I'm having a boy or a girl my doctor won't do a gender ultrasound until 20 weeks but she suggested a place I can pay to have it done sooner is it to soon to try and find out? Should I wait a couple more weeks?  This is my second pregnancy but my first born is 8yrs old and I don't remember how far along I was when I found out about him.