That's amazing dude.
I am seriously considering getting into BJJ. Just turned 49 and haven't done any MA for decades.
I thoroughly recommend it. I just picked up jiu jitsu this year. I love it. It's polar opposite of what I know with karate. There were moments during the Machida seminar when he was teaching us grappling defense and techniques to get away from someone trying to take you down, I'm learning these techniques a striker would use to keep the fight standing but in my head I'm also thinking " NO, why would I want to shake you off? You're right where I want you." in my jiu-jitsu mind. It was also great because in traditional karate training, you are not worried about takedowns... You don't think about sprawling, you don't think about grabbing double overhooks. Lyoto kept using this explanation of imagine if there's an eye on your shoulder, that eye needs to look at the ground. He was describing the motion of someone shooting in on you for a takedown, you grab control of their arms, and the body motion to shake them off coming dropping your shoulder.
What I like about jiu-jitsu is that the techniques that you're being taught, you find out really quick how effective they are for you because you attempt to use them during live training/sparring. You learn immediately if have the technique or not. As opposed to karate, a striking discipline, to learn what is really effective, again you have to spar. But that involves getting punched and kicked. I started karate when I was 6 or 7. Did tournaments. Did not really like them whether I won or loss a match. Felt obligated because I was representing my school, and my parents expectations, whatever.
That's part of why I wanted to go to this seminar. One, sure I'm a Machida fan but you don't have to question if what you're learning actually works... I've seen his fights and what he and Chinzo were teaching us were techniques he's used so the effectiveness is proven. Also, I was partnering with other black belts to practice the techniques. We may be strangers but I trust the process of another black belt, that you've been in this for a long time, so you understand the discipline. We can spar and throw a bit of heat and keep it clean.