I've been on Adventure several times out of both San Juan and Ft. Lauderdale. Had a great time on every one of them. Stop analyzing how you thing you will be feeling. Just go with the flow and take it as it comes. You have friends aboard when you want them and the ability to retreat when, and if, you feel like it.
These days, for various reasons, I mostly cruise solo now and I love it. You might just find that you feel the same. And if for some reason you don't like it, eight days will go by plenty fast enough and then at least you will know if cruising us still right for you. Just enjoy the anticipation.....