I need help from a girl or anyone who can help.?

ok so im 17 years old and i never had a girlfriend or even kiss one. i used to be a chubby kid and now i not really chubby (i used to be 250 pounds, now i am 190 pounds) and i really need help on know how to ask a girl out or how do i talk to one with out looking like a weirdo or it been awkward please help