Don't bother her, just keep her company while she works. Just pick any day not in the month of his actual birthday and throw him a party to celebrate the simple fact that he was born instead of waiting to celebrate the day of his birth. Buy a good quality silk pair of men's pajamas to share between the two of you. One of you gets the top and the other gets the bottom. Drive out of your way to pick her up, hold her dinner chair, open doors for her, read her poetry .
Women love a true gentlemen.
Join the Mile High Club. For instance, a guy can propose to his girl through the windows of the fish tank at the Epcot Living Seas while scuba diving. This is arranged before hand with the Disney people. When they meet on opposite sides of the window, he holds it up to the window for his girl to read and respond. Apparently this causes quite a stir in the observation area with everyone cooing that this is sooooo romantic.