I'm new here too, but allow me to be the second to welcome you aboard.
Congrats on discovering the wonderful world of sailing, and taking the time to attend some classes
is a great idea for learning
the right (and safe) ways to do things.
You have a great boat
there in the P28, perfect for learning
without being overwhelmed. I'd recommend keeping it for a year or two, doing as much overnight type stuff as you can, anchoring
in a variety of places and experiencing lots of different weather
conditions. That's a really well built boat, and she'll teach you alot. Meanwhile, I'd suggest chartering in the Caribbean
as much as you can afford it, and perhaps crewing
for some folks taking their boat down there so you will know when you are ready to do it yourself.
When chartering, you'll be exposed to different kinds of bigger boats, and while you're out there you can make friends with cruisers and get a peek inside a few boats to help you decide what might be right for you.
Just my 2 centavos worth!