I got my bat mitzvah dress on abcfashion.com. Another great place for bat mitzvah dresses is Macys, forever21 or if you have a bigger budget, a prom shop.
At a traditional bar mitzvah reception, party dress are usually worn for the girls, and a nice shirt for the boys.
a dress
It's NOT recommended - except maybe in SOME Reform synagogues.
A Bat Mitzvah girl can wear appropriate formal wear, such as an elegant dress or a pant-suit.
Congratulate her on her Bat mitzvah and tell her you know she did a good job on the bema. Tell her you have been thinking of her but can't make it to the bat mitzvah and that you are sending a small gift. You could find a picture of the two of you and frame it or give her a nice necklace to remind her of your friendship and her bat mitzvah.
Dressy and beautiful
Yes, the idea is to dress nicely!
Girls Bar Mitzvah is called a Bat Mitzvah. A Bat Mitzvah happens when a Jewish girl turns 12 years old. Once the girl reaches that age she is an adult according to the Jewish law. This means that the girl will have to follow all applicable rules. During the ceremony the Bat-Mitzvah girl will wear the dress of her choice.
There is no specific colour worn by the bat mitzvah girl for the ceremony celebrating her becoming a bat mitzvah. Any nice outfit that she likes and feels comfortable in is suitable.
It's appropriate to dress modestly, yes.
any
The plural for a bat mitzvah is a b'nai mitzvah