I'm going to change from Apple to Android, is this going to be an issue for my subscription?

Subscriptions are managed in the Apple/Google play stores. If you are planning on changing this you'd need to contact Apple or Google to see if a refund could be offered.

Google Play help: https://support.google.com/googleplay/?hl=en-GB#topic=3364260

Apple Store Support: https://support.apple.com/en-gb/apps