Apple Music 6 month free on on my phone but I want it on my iPad but not in my account

So I was on my sisters iPhone 15 and I hadn’t reclaimed the AirPods 3 gen offer on my iPad because I use it all the time and I have an android phone.So I accepted the offer on her phone and since I’m 13 and my mom is the family thing iont remember therefore she has an android. So she can’t change the family share and invite my sister and I don’t get my sister’s phone very often so the plan is not in my iPad and I want to use it on my iPad.What do I do?