You should really start looking now. I work in bridal, and it usually takes about 6 months for a gown to arrive with regular deliverey (meaning without a rush order) once it has been ordered. Depending on the designer, some could come as quickly as 3 months, and some can take as many as 9-12 months! You then want to allow about a month for alterations, so you're right on schedule to start looking asap just to be on the safe side, especially since it's hard to make a decision immediately.