How NOT to be Transgender?

I’ve had thoughts about being a guy before, but only few. I figured I am happy enough as a girl to not go to all the trouble. I mean the surgery to physically change would be expensive and I don’t think I could put my friends and family through that kind of thing. I started thinking about it again because of 1 thing that happened. I emailed a picture of me and my cousin who is a GUY (to clarify) to show my sort of ‘email pen-pal friend’ what I looked like. I guess I liked how I looked in that picture and that’s why it wasn’t of just me. Well she replied like this:

omg this whole time I thought you were a girl! I didn’t know you were a guy wow you are hot!

and instead of correcting her and saying I was the girl in the picture. I just said thank you. And the f*cking scary part is that I was HAPPY she said that. Like not only was I a guy in her mind I was a hot guy and that is waaay more than I can comprehend right now. I actually want to be able to convince myself that I will be happy as I was physically born, I will be happy as a girl. Because I grew up all-girl and I’m used to that, and therefore there are many things about being a girl that I like. Like for example I can date straight guys. yay! Bonus for me! But there’s always something missing. And I know it would change everything if I became officially transgendered. I want to be happy as I am outside and inside. My parents barely understand my bisexuality. This would ruin everything. Help?