First of all, my condolences for all your losses.
Santa Rosa Wall is a beautiful but challenging dive, and should not be your first o/w dive after 2 years. If I remember correctly, it had a pretty good current and was essentially "bottomless" at some points. It requires you to be comfortable with your equipment, your skills, and your buddy. On the first dive, you won't be sure of any of these things.
On the first dive, you could do a shore dive and check your weighting and your equipment. If you're concerned about equipment, you could rent equipment that you're familiar with from your Local Dive Store and take it with you. You may even be able to try it in the pool to make sure you're comfortable with it. Does your LDS have pool sessions with instructors available? They can help you practice your skills and maybe even do a refresher course. A refresher course here costs $25 (that's Canadian!), so it may be cheap there too. They should be able to give you some tips on drift diving as well.
It doesn't sound right that this Cozumel dive shop knows your history, knows that you are uncomfortable, and would still schedule this for your first dive. Perhaps you might want to check other dive shops.
I don't know which shop you are booked with, but I've spent 2 weeks over 2 years with 2 entirely different crew with
Aqua Safari. I have found them to be very watchful and very helpful. I have seen them signal to people to go up a bit and even go right up to them if they're not paying attention, even if they seem to be only a couple of feet below the planned maximum. I've seen them give lots of advice and go out of their way to help people perfect their buoyancy, etc. They matched divers (novice, advanced...) to boats and were very particular about who could go on certain dives like Punta Sur - Devil's Throat (awesome - beautiful dive!) and they watched all week while we essentially proved ourselves. I've also done a few dives with Dive Paradise, and found them to be quite good as well.
Having said all this, I also realize that in warm water and amazing visibility, there are less complications and you frequently see o/w divers diving to around 100 feet. After all, the 60 feet is just a
recommended limit. Also at most of the dive sites that they will probably take you to (unlike Barracuda wall, Punta Sur, Maracaibo, etc.), I found the current pretty light - it's a nice slooow drift. Probably after 2 or 3 o/w days, you might feel comfortable enough to go deeper.
Sorry to be so long-winded. Hope this helps! :sunny