Should she be pissed?

ok so i told my best friend that a dated like a year ago. (we dated for 2 years and have been best friends for one) i would take her to a newly oping restraint to try some pizza. we have been looking for good pizza for a while now. but oping day comes and i take another girl on a date. the pizza was ok. now i have been on other dates with other girls before and she never cared in facet she was happy for me.but when i told her i went and she completely flipped. she said that i promised her to go with her and that someone Ive known for a week should not have had the experience. i told her i still planed to take her and she said she wont go that their is no pint because ive already tried it and we were supposed to try it together. so is she over reacting or did i do something wrong and should i make up for it