I was about 13 years into Uechi Ryu before I began studying ju jitsu. I personally was nervous about it because I feared putting stress on joints and locks that can easily cause breaks. However, I jumped in anyway because I knew enough to know that my ground fighting and grappling skills were poor. (INMO, anybody who thinks their Karate skills are good enough to keep them off the ground and out of an attackers grasp is kidding himself.) Now several years into ju jitsu, I thoroughly enjoy it and consider it a natural complement to Uechi. Anything that makes you a more complete martial artist is beneficial. If you train for knowledge rather than rank, then you will find you have time.