And this is probably the most important advice, although I can't say I agree with all of it.
The point is, find something you enjoy doing, and do it.Be it weights, body weight training, cardio is running or swimming etc or rock climbing or support via a game like football or rugby etc.
If you choose weight training but you don't like it, you'll be less prepared to do it and you simply won't do it.
So try different things, find something you enjoy and do it! For me, I love to challenge myself doing weight training and I'm loving how my body is changing, even though it took me 2 years to find what works for me in the gym.
This ^
I'm forever telling people this when they ask me for fitness advice.
Problem comes when you enjoy doing it once you get started but need to overcome the initial inertia! A bit like jumping into a cold swimming pool.