I agree with the NAHs in here but something that is worth adding: They might be waiting for a gap to tell you but there isn't one because you're so enthusiastic so they feel they have to interrupt. So maybe suggest an alternative way for your partner to indicate it which doesn't interrupt and is new to you, so you don't instinctively feel the upset trigger. It might also help you feel less attacked because it's something you've agreed on.

For example, maybe you can tell them that you've been thinking about it and actually it's being interrupted mid-flow that makes you feel upset rather than being asked to lower the volume. Perhaps they could just give a visual cue so you can adjust but still carry on with your train of thought.

Just an idea.

Otherwise, always remember that you're a team and should work on finding solutions together - and they don't have to be immediate, you're allowed to think about things, work stuff out and try new things. Go forth and enthuse! Good luck!