first thing to understand is drawing has NOTHING to do with talent. it's a mechanical skill, and you only improve through mileage. draw, draw, draw. ANYBODY can reach a photographic level, it just takes repetition, repetition, repetition. there are no shortcuts, everybody who's any good has drawn thousands and thousands of drawings. your age doesn't matter either, you can start at 50yo or 5yo it's all the same. it's never too late.
start drawing every day. don't worry about how shit you are, just keep doing it. the most important thing is keep doing it. don't wait for inspiration, just do it. and keep doing it.
start with the fundamentals early. drawing cubes in perspective, lighting them. balls, cones. then learn about construction. google it, it's important. fundamentals are boring, but if you start anywhere else you'll eventually have to come back to it or your work will look amateurish forever.
or do it backwards like we've ALL done, but know that it just can't be skipped. you'll have to come back to fundamentals sooner or later.
that said, don't forget having fun either. draw tits and dicks if you like, it doesn't matter. whatever you like. humans/animals are the hardest, but also most fun. just make sure you learn about construction first, it's absolutely essential for bodies. they won't look right if you just freehand them, doesn't matter if you draw for 10 years. it's good construction that gives those awesome drawings you love their precise strong forms. it's not the shading, it's not the polishing. without consruction everything looks a little wonky, amateurish.
there are many construction methods, but it doesn't matter which you choose. all of them do the same thing. just keep using the same method of construction until it becomes a second nature. that's the aim here, making it a second nature.
shading should be the last thing you should worry about. it's natural that we all start trying to perfect shading, but it's 100% polishing shit until everything else is in place. and even then you probably won't need it, in fact you'll probably want the opposite when you're good.
so in a nutshell:
1. draw every day. keep at it. doesn't have to be great art, picasso drew pigeon feet obsessively over and over and over again, and at 18yo he was at master level. nothing like the shit we know him for, he did masterful realism in his youth. it's all about mileage and repetition. treat it as a job or a duty, not as something you do IF you feel like it.
2. learn about construction. use it to draw that cat if you want, keep doing it over and over. different poses, different angles. you'll get there. repetition is the key, daily grind.
3. shut up and keep drawing. watch painters doing their stuff on youtube, it's great fun and makes you motivated again. remember they were ALL shit at the beginning as well, every single one. they just kept drawing even if the world burned around them. and especially then. make it your own thing, make it your escape from shit.
you can do it. it only takes daily repetition. everything else you'll learn on the way.