Question about birth control?

Hi, i am 15 and my mom just told me she thinks i should get on birth control. im not sexually active, and i never have been. im still a virgin and i plan on staying that way untill i get a boyfriend that im searious about. she said that she just wants to get it out of the way so she doesnt have to worry about me having unprotected sex and to help with my periods. but, i dont think my pierods are that bad. i got my frist period when i was almost 12. my periods come almost exactly every 25 days(give or take a day) and usually last about 4 or 5 days. i dont get cramps. well... sometimes i do. like every 3rd period i have cramps just on the frist day but i basically dont get cramps. i dont feel anything actually. my back just aches and my body gets kinda sore but im good with pain so it doesnt really bother me. so its kind of like my period isnt even there. but she said she just wants to make sure im protected just in case and to help my periods. she said that they will come less, and stay for a shorter amount of time? is that true? ive been looking up things on the internet on if it effects girls moods and i really cant find a whole lot. im not a moody person, im pretty mellow. i dont get emotional all of a sudden or anything....all my friends say their jealous, but like i said....my periods dont really effect me. my question is, if i start taking them will they lessen my periods like my mom said. and will it make me all moody and crap. because im not like that now and i really dont want to be. i have friends who will just start crying for no reason...and its wierd. i like how i am now. but i do want to be protected and have less periods, i just dont want to be moody and emotional. sorry this is really long.....i know theres different kinds of birth control and i just want to know if you were me, would you get on it? and if its a good idea or not?