Before I give you my opinion, I just think it's great that you compete at all. How wonderful!
If I were you, I would never give up a dream, however, sometimes the only way to realize that dream is to know when the right time to strike is. Perhaps that's not now for Latin, but you could make Standard your stepping stone for the moment. Maybe by allowing your BF to realize his dream of competing in standard, he'll repay you by doing latin when the time comes. You say money is tight, so maybe focusing your resources on one thing will be more beneficial that you thought it might be.
If you give standard a try and you know you must do Latin to be happy, then you'll know that it's time to really push forward and fight for your goals as a Latin dancer too. You may have to save a little to fly in good coaches, but it will be much more worth it than wasting money on bad coaches. I don't think you should worry about your ankles or knees. That type of thing has a way of changing as you train.
GOOD LUCK! And happy dancing!:)
Jeravae