I'd have to agree with the sentiment of "Wait until you're 70".

As long as you're holding threat and not dying, you're fine. Do some Roulettes at 70, some Lv70 content, and ease into improving your rotation bit-by-bit. Start off being a bit cautious and then dial back on the defenses a little until you see what's good to do and what's not good to do. Get better at the job gradually over time, instead of trying to cram everything into your skull all at once and then you show up to a group and you're "uh uh, I think it said to do A B C... or was that A C B?" and next thing you know, a BLM drops dead because you were fumbling over your keys worrying too much about trying to remember what you read and trying to follow it to the letter.

You need to build muscle memory and you do that by just playing the job. Play it. Go solo some crap, practice the rotations. Tweak your hotbars until you can hit buttons without even looking at the hotbar. That's what Muscle Memory is. Your conscious mind says "I wanna use Rampart" and your subconscious brain translates that into Ctrl+3 for example, without you even going "uh, where's Rampart again?"

This takes time to do.

I just got mostly done with RDM, and I'm to the point I don't even have to think about where keys are. My fingers already know, by themselves, what to do in what order. And if some emergency pops up or something, I'm comfortable enough with the job I can usually handle it.

But if you try to cram it all in there from reading a guide, an emergency pops up, you won't know what to do usually, you'll be like a deer in the headlights, that situation where you just lock up and go "uh...." and before you know it, it's a wipe.