Like the celebs on Strictly. What should I be doing now?

Imo it does have something to do with genes as well as fitness. I couldn't do them when I was a skinny child, so couldn't realistically expect to do them in later life!

You have to go to the gym to stretch, stretch, stretch, and keep your weight well inside BMI limits and exercise every day, doing yoga or ballet or other movements that keep you stretchy. Every day.

But otherwise, there's nothing to it.

Every day Could I have a 5 year break at some point?

I did them unintentially when I slipped on the ice, never done them before, hope I never do them again!

Or you could have some surgery done to the tendons on your inner thighs - have them cut through and replaced by stretchy elastic.

Might make you walk a bit funny, though. You might need to tie your knees together in order to remain standing up.

I was hopeless at that kind of thing when a child too, although I was very flexible and still am, but in my late 50s/early 60s I went to aerobics classes followed by 30 minutes of Pilates. After only a few months I could do the splits. It's just a matter of learning the technique and practice, practice, practice.