Hey Nick - I know I’m a lil late here, but just wanted to say WELCOME. Good to have you here. WOW! Mandolin!! One of my favorite instruments. I’ve tried playing a couple times, and it takes a lot of hand strength.
My first instrument was guitar, and as I wrote about recently here, pain in my hand was what drove me to playing the harmonica, and I’m now so grateful for that!
As @slim always points out, prior experience on another instrument is always a huge leg up on your harmonica journey, so you’ve got a jump start. Hope it is going well for you.
Rock on,
Luke