use using the wrong words

Today I spoke with my flatmates about my retainers. I told her that my retainers came off and I needed to go to the dentist. I told her I am was gonna ask the dentist whether she can "pick my retainer out" she looked confused, I guess because of that. What I meant was "take out" instead of "pick out". I was aware that I chose the wrong phrase but couldn't find any suitable worlds. It's quite pissed me off when I didn't know the right words or phrases.

Anyhow, at that time, I wasn't ready to speak in English mode thats why I hesitated. I was also a little bit nervous since the other party speaks English fluently like a native. I have a tendency to feel a little bit nervous and shameful to speaking English in front of native people or those whose speech is similar to natives, however if I face others whose the speaking ability of speaking is the same as me mine, I don't won't feel that way.

ps: Your english is pretty good! Just some minor errors. Have confidence and speak proudly! Making mistakes are an essential part of improving :) Great job!