Go for it! I'm a female too and my first car was a 1992 Ford F-350 diesel with a seven inch lift and oversized tires. I used to work in an auto repair shop. (They weren't hiring for mechanics at the time, so I worked in customer service, but I have known several female techs and am working toward being a mechanic myself.)
The best part of being a female mechanic? You make the guy on the other side of the repair desk look stupid when he tries to take advantage of you because you're a woman!