Irregular period?

I can't tell if my periods are regular or irregular. I think they are irregular and I am considering birth control but I'm not sure yet because I'm not sure how to ask my mom for it. So my period in the last few months have never came on the same day because they are either a few days early or a week late. The length has varied a lot too because they always last longer than a week and I have had a couple go 2 weeks before but usually they are around 8-10 days long. I can't say that the periods are very heavy but I do have to use the super tampons because the regulars just don't work as well. The cramps are not as bad because I have a high tolerance for pain but they have been getting worse every month and the pain is going more to my back now as well as my stomach, and pain killers do not really help with the pain. I would just like some feed back on what I should do regarding it and if anyone else has these problems.