How old are you subtlety? Just curious. If you're only 18 or something, obviously you're too young to be thinking about settling down for life yet and probably have sex very much on your mind. Even so, it would be OK to be looking for a 'semi-serious' relationship with a girl (that would be an exclusive relationship that you both hoped would last at least a year or so) even if only for the practice, to learn about life and love and all that stuff.
If you're in your 30s it would be about time you had already figured some of this stuff out about 'girls' and what they like and don't like. It would certainly be about time you were starting to get serious about finding someone you really liked and might want to stay with for an extended period of time. Your choices will start to thin out by the time you reach 40, believe me. The 'good ones' will tend to be taken.