you can't spot reduce fat, but if you have lots of fat on a certain area, it's likely that your body will cut into this first. For example, i lose crap loads off my tummy whenever i lose any weight, it gets beyond flat, even when i think there's nothing left on my tummy to lose it keeps getting smaller before the rest of my body does a thing! you don't lose the exact same amount all over your body - that's why people have different body shapes. it is likely you will retain the same 'pear' shape, but you can definitely reduce the size of your thighs.
i don't know wtf some of these boys are on about but it IS very important as a girl that you do not overuse any weighted leg machines. Even my gym instructor told me that it is very easy for girls to build thigh muscle which has the effect of bulking (as well as toning) so be careful. but rowing is good exercise as it's mainly cardio but also has subtle toning effects without the bulking that weights can have.