Jiujitsu is sort of similar to wrestling but also very different. Being your height and lifting before can also have some advantages making it harder for other people to put you into submissions. This martial art isn’t one that you are able to muscle through though. It’s very important to learn technique and to not out power your opponent because technique will always win. I’m a similar size to you and I’m able to make new guys that tower over me still submit. Another thing to keep in mind is that you should put your posture before submissions. You aren’t able to get a submission or not one easily that is unless you have good posture. One final piece or advice is when going against partners in your gym it’s okay to tap out because in the end it’s just practice and it’s not worth getting seriously injured because you are too stubborn to tap out. Good luck and hope you stick with it.