She wants to switch from French to Spanish for MYP grade 10. The school says she'd drop a phase

Our daughter has done French since grade 6 and has never liked it. Her two closest friends take Spanish, and she's been picking it up from them and from a series she watches with subtitles. The school will allow a switch for grade 10, but she would go into a lower phase, and the coordinator warned that her language grade may dip in the year that counts for the MYP certificate. She is completely sure. I'm worried it's mostly the friends and the series. Has anyone's child switched language late in MYP? Was the dip real, and did it matter for DP subject choices afterwards?