I gave away my parents gift.

My (16m) parents gave me a $25 Starbucks gift card for Christmas. I go often but my sister (14f) and her friends are obsessed. I sort of told the girls if either of them wanted to use it up and not say anything it’s cool. My sisters bestie jumped on the offer and took my gift card. She assures me it will be spent and gone and parents won’t know anyway. I really don’t want to tell my parents I gave their gift away but would that be wrong?