I have been traveling alone to the DR since 2005. You will absolutely get a lot of attention but as said above, say no and live your life the way you want to. You can take the approach of being closed off and reserved which will make you unappealing prey or you can be friendly and participate and let it be known that you want a good clean vacation with the intention of going home as you arrived.
Since 2005 I haven’t heard that women traveling alone are the victim of thefts or other crime on the resort any more than couples. Make sure you know where you are and with whom if you leave the safety of the resort. That doesn’t mean you shouldn’t leave the resort, just do it with the appropriate amount of wisdom that going somewhere unknown in a foreign land has associated with it.
You may find like many of us do that once you travel alone, it’s hard to travel with another person in the future! If not hard, at least you’ll look back on your solo vacation with fondness and look forward to the next one.
I find that my vacations when I travel alone are different from those when I travel with others for reasons one might not anticipate. If I’m with a Dominican, the resort staff tends to speak to them on behalf of both of us in Spanish. At the same time, when I meet a confused face I tend to immediately let the Dominican translate for me and I don’t try harder to communicate like I do when I’m alone. When I’m with my mom, the dynamic changes and the staff want to take care of her instead of the way I get to know people when I’m on my own.
Enjoy the freedom that traveling alone affords you too! Do what you want when you want!