cowprintrabbit:
Our friend is a DM, and has his own boat...
Its good you recognize your limits and are exploring before you go. That's a good sign!
There's a saying about Abaco, another island group in the Bahamas, that is isn't for sissies. I've always thought that applies to Bimini as well. But I really enjoy Bimini. Its water is beautiful, and the folks there are nice. But it does not have the type of infrastructure most visitors expect, and it can surprise you if you aren't ready for it. For example, you might find yourself brushing your teeth in brackish water; many roads aren't paved, etcetcetc.
But the diving is fantastic. If your DM friend is worth his or her salt as a DM, and if you pay attention to your skills and dive plans, you'll very much enjoy the dives and learn a bunch while you're there. But remember you are a long way from help, so pay attention to currents, depth, and your ascent rates. And talk to friend/DM about the need for you all to do a couple of warm up dives once you get there. Too often, the more experienced folks hit the islands and immediately want to go do the deep walls. That's not where you should start in Bimini.
You'll find some fantastic simple and shallower sites. The fish life is awesome, and turtles are common. You'll also see grouper that are fairly tame and will explore you. There are sharks, but they tend to be shy unless someone in the group is hunting.
Be aware that the visibility is usually very good, and that because of this, the depths can be deceiving. You might think you're exploring along a wall at 40 feet, only to have dropped down to 75' or more. Pay close attention to your depth and air when you are on the drop-offs.
I'm attaching a link with a write up I did for the South Bimini Yacht Club a few years ago. I just noticed that its still posted on their site. Had a nice trip with a dive club there, and you might see that I enjoyed the trip.
http://www.scubabimini.com/scuba.htm
Go. Enjoy. Then come back and write a trip report for us so we can dream that we were there too!