[M4F] Older brother comes home from college to find lil sister has hit puberty

I am your older brother who has been away to college for over a year to college. Growing up we were very close. Even with friends and girlfriends I always made you feel special. I received a football scholarship but it was out of state.
I decide to come home and surprise everyone. But the surprise will be on me, as mom and dad decide to leave alone for first time as they take a long weekend getaway for their anniversary. Leaving the house to just us.
When I went away you were a flat chested tomboy, coming back you are almost unrecognizable taller, curvy filled out, a gorgeous young woman. Puberty has hit you good and hard. Your hormones have you curious and horny.
I have become more of an athletic stud, following the strict work out program set up by my coach.