How can i confront my mom about tampons?

Ok so my mom told me i could start wearing tampons and she showed me how to use them and all ( even though i already knew) and she said we wwill go to the store and get some that are eaiser to slide in like better applicaters, anyways its been like 2 weeks and she has t taken me yet and i want to confront her and ask if we can go look because im going to a workshop soon its dance and i thunk im going to get my period then and i HATE pads.. Anyways i was going tomask her today when we were on the road to costco but anytime i would want to say it my mouth wouldnt open or no sound came out... I knew what i wanted to say but i coulndt say it...i dont want to text her or leave a note but how can i confront her and actually ask to get me tampons??