Can I back out of a Real Estate contract?

I am getting worried because our realtor showed us 4 homes in a subdivision that we liked. We wrote offers on all of them and have submitted them. One of the homes came back way too fast and accepted all of our terms and then we got worried that the home may be overpriced and that is why they are so hurried. We signed the offer and the sellers signed the offer and my realtor has a copy of it but she has not put a Binding Agreement date or acceptance date on it yet but all parties have signed it. She is says she is waiting on a response from the other offers before she sends it back to them. If the other offers are accepted and I like one of those better, will I owe any earnest money to the first sellers since they accepted our offer but we have not sent it back to them? How do I get out of that offer?