Bubble Tea is my shit, so I got some things to say. For starters, try a fruit flavored one that is known to not be too sweet because the ones like strawberry, lychee, and jackfruit can be sickeningly sweet when in the wrong hands. There is a slight chance that it could be powder-based instead of real fruit, so mango is typically a safe bet for me.
Now for actual tea-based ones instead of fruit based, watch out for the caffeine. Thai tea bubble drink is especially strong, so start off with a low caffeine one again. It's also not on the sweet side, so green tea is my recommendation for this.
Boba, otherwise known as bubble or tapioca pearls, are usually the kicker that can make or break the bubble tea experience. Good places usually have more boba that is nice and chewy while newbie places would have a few frozen or "bad ones" in there. They don't have a taste and the texture is quite chewy. Since you're kinda new, you can either dive head-first into trying it or opt out for a fruit jelly substitute since it adds to the sweetness and is less chewy than boba.