Bat Mitzvah Dress!!?

for my 13th party (bat mitzvah) i am going dress shopping. i don't know if i show bring my BFF. she did not bring me when she got her dess. but i don't know what to say. i told her that i was going today (febuary 3) and she just looked at me. i loved her dress at her party and that was the same one i was going to get today. I saw one that was a little different but i dont know what she would say about it. My fav color is light blue and her's is pink. but her dree was blue at her party soooooo...... PLEASE HELP ME!!!!