Understand that kegel exercises does help in some way. Need to keep on doing kegel exercises for 6-8 weeks before you see improvement just like you are building up your other body's muscles group.
I am more than 45yo and luckily is able to still keep it up for between 20-45 mins (still occasionally probably hit more than 60 mins with my fb- don't really time but estimate from time book in to hotel) from time of penetration.
I practices a bit of qi exercises that channel to my lower abdomen area. Still wake up in the morning with the flag pole up when I don't have sex that night before.
Have a new SB this Aug and help her to 5 orgasms in our first session. She claimed that she had never had multiple orgasms before with one penetration as her previous experiences with other guys are only 5-10 mins and she needs longer to come probably, or not enough fore-play. But nevertheless, I believe kegel exercises will help.