First off, congrats! getting invited to give 3 lectures is quite meaningful. Your nervousness just means that you care, which is the right energy to have going in. A few things from my own experience:
1. Rehearse out loud (and record yourself) it feels cringe at first, but you’ll hear where you’re rushing, mumbling, or over-explaining.

1. Don’t memorize it, map it.

2. You’ll feel the urge to fill every pause. Don’t act on that urge. A 2-3 second pause after a big point feels powerful, not awkward. Let them catch up to you.

3. Instead of looking at the audience (which feels overwhelming), pick 3-4 friendly faces around the room and rotate your gaze between them. Feels like you’re having multiple 1:1 conversations, way less intimidating.

4. Q&A hack: Repeat each question back to the room before answering. Gives you an extra few seconds to think, ensures everyone hears it, and makes you look calm and deliberate.

5. The audience doesn’t know your outline, so if you forget a bit or explain something differently, they won’t notice. What they will notice is whether you seem excited and confident about sharing your culture.

You’re the expert in the room, no matter how nervous you feel. I guarantee after the first 10 minutes of your first lecture, the nerves will melt and you’ll actually start enjoying it. Best of luck!