Unfortunately you do not say if you are already having periods, or you just want to be prepared for when they come.

Having a strict mom can be scary, but she is still a mom and a woman. She has gone through puberty herself and know what you are going through. She has your best health as her top priority, even though it may not always seem that way.

Wait until you are alone with her and say "Mom, I think my periods are getting close and I want to get some pads to be prepared".

If you are already having periods, just ask if you can get money to buy your own pads, or if you can go with her to the store to buy pads. It is actually the easiest to just ask before you use all your pads "Mom, my pads are almost all used up. Can you please get me more when you go shopping again". Or you can write her a note or send her a message. When you ask your mom to buy it, remember to ask exactly for what you want. There are so many types and sizes of pads, that you must ask for exactly what you want.

Take care