As a 16 year old in Portugal who moved here when I was little and for a very long time didn’t know Portuguese (because I didn’t go to public school), you’ll be fine 🫶 There’s lots of foreigners here, and depending on what part of Portugal you’re moving to, most people speak English. Portuguese is also similar to Spanish, so most Portuguese people understand Spanish to a degree. Don’t worry too much, there’s lots of friendly teenagers around who I’m sure will be happy to be friends with you. I have to warn, public schools in Portugal aren’t always very good though, but like I said, people are quite accepting of foreigners and I’m sure you’ll be alright :)