My mother has always hoped that I'd be married in her wedding gown. It's really beautiful, and I'd love to wear it, but my mom is four inches shorter than I. She's petite while I'm more full-figured. She's offering to have her dress altered for me, but I'd rather get something new that really fits. How can I get out of this without hurting her feelings?
Wearing an heirloom gown is a wonderful tradition, when it's practical. Because of the differences you describe, however, your mother's dress would probably need to be completely remade. When you talk with your mother, be sure she knows that you would really like to wear her dress if you could. (You aren't criticizing her taste.) Be respectful, but also be clear that you won't feel comfortable in a dress that doesn't suit you. You might also talk with a seamstress or tailor who can explain to your mom how extensive the changes would be. Then involve your mother in your dress selection; seeing you in a beautiful gown is likely to cure her disappointment. If it's feasible, incorporate something from her wedding (a piece of her jewelry, some lace, or her veil) in your outfit--a loving way to show much you appreciate your mom and to create a new family tradition.
Here are some suggestions for alterations to other traditions.