I used to have very strong muscles and now I do not have money for a gyno exam.

Submissive - yes, they are well worth doing, they protect against urinary stress incontinence that plagues aging women as well as supposedly improve vaginal sex. I used to do them all the time and enjoyed doing them and I used to be able to bring my ex to his orgasm without his movements - just by my squeezing. Then we separated and I became celibate and stopped practicing completely forgetting, stupid me, that those are UROgenito muscles - not just for sex but for the URO part. Stupid stupid stupid choice. At any rate, after several years it is very hard to start from scratch. You are awfully young to think about urinary incontinence but you can have more fun in the bedroom squeezing your partner's penis.