To the OP -- The fact that you are asking questions is a good sign.
Chac Mool is a big, open cavern which would be hard to silt out. You would know if the guide tried to take you somewhere you shouldn't be, because you will leave the gold line, and probably pass a big sign that says either "Stop", or "Peligro".
I do think that divers with as little experience as you have should mostly think twice about the cenote dives. They are run with a very good safety track record, but the two times someone is going to get into trouble are if they follow a guide where they shouldn't (and you can control that) or if they cannot cope with a simple diving problem without surfacing, because honestly, in a lot of places, you can't. If you haven't dealt with a flooded mask or a lost regulator or a leak for real, you just don't know what you will do when it happens, which is why I think folks should dive for a while before doing the tours. However, the sites are stunningly beautiful and unique, so unless your trip is jam-packed, I'd highly recommend a tour to the cenotes and perhaps a snorkeling adventure. They're worth seeing.
Chac Mool is a big, open cavern which would be hard to silt out. You would know if the guide tried to take you somewhere you shouldn't be, because you will leave the gold line, and probably pass a big sign that says either "Stop", or "Peligro".
I do think that divers with as little experience as you have should mostly think twice about the cenote dives. They are run with a very good safety track record, but the two times someone is going to get into trouble are if they follow a guide where they shouldn't (and you can control that) or if they cannot cope with a simple diving problem without surfacing, because honestly, in a lot of places, you can't. If you haven't dealt with a flooded mask or a lost regulator or a leak for real, you just don't know what you will do when it happens, which is why I think folks should dive for a while before doing the tours. However, the sites are stunningly beautiful and unique, so unless your trip is jam-packed, I'd highly recommend a tour to the cenotes and perhaps a snorkeling adventure. They're worth seeing.