Sometimes this is done with a new development due to need for certain types of financing. An example of this might be that the property is awaiting FHA approval. You didn't specify if "your agent" is your buyers agent or the listing agent but you should get a clear answer as to why this takes 10 days. Also without knowing any specifics of your offer or how it's structured that could affect the process of getting an offer accepted. Many builders are going the route of having an attorney review all offers, some take some time doing this (10 days does seem a bit much though). If you're financing this purchase you'll be using the services of at least your lenders attorney but these are the types of situations where having your own personal attorney involved earlier in the transaction is very important. You should ask friends, family, colleagues for the name of a real estate attorney they've used recently and been happy with. Then take all your documents, copies of offer etc. for them to review. Most all will give you an initial consultation for free anyway. If "your agent" is your buyers agent and not the sellers agent or a dual or designated agent you could also ask for a referral to a real estate attorney they work with regularly. Where you sound like you may be involved in negotiations with the developers attorney, having your own attorney will protect your interests.
Hope this helps,