I'm really good at accents because I imitate exactly. People think I'm a native when I say hello then I can't understand anything after that because I'm really

I'm really good at accents because I imitate exactly. People think I'm a native when I say hello then I can't understand anything after that because I'm really bad at remembering vocabulary. It's kind of scaring me off moving to another country to learn the language because I struggle to remember words in English. At the same time I know I would master the words and phrases I do learn plus I've always wanted to try being immersed in another culture. Terrified of not being understood I guess.