I have heard of some people who have done this though, whose progress got deleted after linking their email.
Just make sure you sign up for your account through your device, where you have your data. Everything should work fine.
The people who lose progress did something weird, like creating an account on the website and then signed into that account on the mobile app. Or they created an account years ago, but played on the mobile app without being signed in, so when they finally sign into their old account they're surprised their old account doesn't have their new games.
If something does go wrong you can always contact me by going to Help -> Contact -> Report a Bug
Edited 4/27/2020 01:24:33