Bat Mitzfa money and dress?

im going to my first bat mizfa ( sorry if it is spelt wrong) it is tommarrow. im not jewish so imm not sure what to do there!! i have a mandatory sports practice that i cannot leave early or miss. so i have to miss the temple. i got a pink dress with lace flowers on the bottom and a black elastic stripe in the middle . the dress is actcully a peachy color. i dont know if it is appropriate or not. the shoes, i havent chose between coach flats, white coach heals white or multicolored pinkish jack rodgers. and how much money? shes been an okay friend for 4 or 5 years we have gotton into fights. i know its multiples of 18 so im not sure if i should do 36 or 54. please help! thanks so much