You can teach an old dog new tricks.....(or not).
Having said that.....
IRL...some people are just not sexually compatible, and trust me.... it doesn't (naturally) get better with time. So don't be afraid to bring up what will undoubtedly be one of the most difficult conversations of your life (so far....LOL). In the end, people only change if they want to....and education is the key (there has been a plethora of information about sex and sexual pleasure, and sexual dysfunction published).