The beach itself looks exactly the same! Just a whole lot more development around there.
When I was a senior in HS, I did a school trip to Merida. We did a few side trips (one involved going to a town with one bathroom and sleeping in a hammock in a shell of a house. At that age, I was not prepared for that!), including Tulum and the ruins. I mostly remember climbing up the pyramid at Chiken Itza and being scared to death to go down. I actually went down on my butt, which took a very long time. A foreshadowing of my dislike of descending on a bike! My other memory is of course, being able to drink at age 17, and learning about rum and cokes.