Get a 125 DT or some thing to get used to, they don't go that fast then move on to something else when your confidence grows.
My Sister did the same and after 3 months riding a put-put she got bored, took the big bike test and got a 600-somehting-or-other ............ she is a girl, so you can do it too
Go for it
Bike are fun and an adrenaline rush ....... but safety first and all that
I fancy doing the same, and want something that goes "potato, potato, potato, potato, potato, "