Looking For A Dress

I`m getting married next march but I would like to try and find my dress sometime in the next few months to when the seasons are changing. I prefer not to order a dress because I would like to try it on before I commit to purchasing it. I`m looking for a size 18 white gown. I prefer to have some sort of covering on my arms whether its a shaw or off the shoulder sleeves. Please let me know if there is anybody in the Tyler, TX area that has dresses or knows of local vendors. Thanks