Don't be nervous, I think you will fall in love with cruising just like the rest of us. My first was a 3 day to the Bahamas also, to test it out. I just came back from #8 and only took the first one 5 yrs. ago. The only thing that should scare you is that you will become addicted and want to go all the time! By the way, I have been to Tulum. It is a beautiful site right on the ocean, amazing what the Mayans did way back then. Enjoy!