Most Helpful Girl
I cannot see how a dirt bike could be considered nerdy or attractive. There are a few 'teenagers' who ride them in my local village and they are looked upon as annoying but they tend to use them for fun rather than transport.
However having your own transport is always good and a big dirt bike will always trump a moped/scooter. Just make sure you always carry a spare helmet for the girls. They will appreciate that.
Personally I would get a street bike. I own a Honda VFR400 myself.
Most Helpful Guy
Getting a motorcycle can only help. It is the one way that younger men less affluent can go toe to toe in terms of vehicles with wealthy older men who can afford muscle or luxury cars, Something about motorcycles will make the bras unhook and the panties drop.
However, if you live in a mostly urban or suburban area, you are probably better off with a street bike.