How can I get more comfortable giving presentations in front of large groups?

• Never try to memorize a presentation word for word: This puts your mind into a very anxious and fragile state where the second you mess up and go off-script, everything falls apart. Memorization in general is a very dangerous technique as it really taxes your mind and is rarely the best option.
• Have high-level slides with just the core ideas and push yourself to fill in the gaps. So define ~10% of the presentation and fill in the remaining ~90% on the fly. Being able to "wing it" is a very important skill for a strong senior+ engineer.
• Do mock presentations before the actual meeting. Either do it in front of a mirror or with your peers/manager/mentor figures.
• If you have a truly good and supportive team, remember that you're not being judged, especially since you're currently working your way towards senior. If you mess up, there's no real consequences - I'm sure your teammates understand that you were nervous and that you're trying to get better at this skill.

Related resources:

• Alex's Guide To Effective Communication
• "How to improve my English communication?"