Presentations are like breath mints. Never turn down an opportunity to have one.
Polite society won't tell you when your breath reeks, they'll just offer you a breath mint, so never turn one down. Likewise, polite society won't force you to present your ideas, so a lot of interesting ideas remain undiscussed because people don't bring them forward.
Giving a talk does several beneficial things for me:
Society benefits when people share what they're doing. So give a quick lightning talk on something. After you feel you've mastered the 5-minute talk, try giving a longer one. Just go for it, your user group will always support you.