It's a two steps forward one step back process. You'll feel awesome just for sitting a trot and canter - but after you manage to do that, you'll realize you'll spend years 'doing it well', and have good & bad days with the long process of perfecting your riding...
jumping is all flat work. Particularly if you're older and safety is a priority - it's better to focus on that. Sure, do a small cross rail when you feel up to it.. I think I did my first 4 or so months in... but I can't tell you how much better / solid it feels now that my legs and core are stronger - and I'm sure that will only improve in time too. I'm still focusing on Flatwork primarily (I'm 1.5 years in on this adventure).
as adults we tend not to bounce when we hit the ground anymore. So safety and minimizing that is always a priority for me.
Also - if you really want to be a better rider, suck it up and start doing cross training. Core exercises, squats, etc. They (Trainers) will tell you to use your leg in ways that take muscle - all while saying "but keep it relaxed!" (!!). Well, the only way to do that in my experience is to have a strong leg and not have to turn red in the face trying to use it effectively.
oh yes, and who ever said it would take over your life.. is probably correct. you'll start at once a week... good luck with that. :) I can't believe all the money I put into horseback riding these days.. but somehow all worth it.
Re: any of my advice - Happy to give my two cents, but not an expert... just a girl who loves riding horses!