Cressida81, first of all, Congrats and welcome to the hobby!
As for your "bad" signal report, it's also possible that you were just in that ONE spot that was bad. It's possible that if you moved your antenna just a few inches in any direction, you might find that your signal might improve to the repeater. Think of it like this, as you're driving, you'll notice "picket-fencing" of the signal, where the signal strength goes up and down as you drive. If you happen to stop in one of those nulls where the signal is low, sometimes just inching forward a few inches will help.
Talking about Mic Fright... Yes, I used to suffer from that when I first got my license. I had no idea what to say! Now you can't get me to shut up, I am notorious for timing out a repeater, and all of my radios have a RTL (Release to Listen) button instead of a PTT (Push to talk)
The big thing is, just treat it like you would a conversation at a bar. You hear a few folks talking about something you're interested in, jump in and introduce yourself. Or, throw out your call when the repeater isn't in use and see who will come back to you. Simple things like what you do for work, the weather, cars, other radios, etc, can be good topic starters. Even though everyone might know everyone else, they all had to meet each other somehow. Just start talking to everyone and eventually you'll become a "regular" like they are. Remember common courtesy, don't interrupt a conversation unless you can contribute to it (don't change the subject!) and just treat it like any other casual conversation. Thankfully in ham radio, there's no procedure to follow, just start talking!
One final bit of advice... Ham radio is just like the real world, meaning, there's nice people and there's jerks. Some groups will be inviting and eager to meet someone new. Other groups are full of people that have known each other for decades and they're not too keen on letting someone new into their group. If you run into the jerks, don't sweat it. Just find someone else to talk to and don't let the old farts get you down. At the end of the day, it's just a hobby and should be enjoyed.
Good luck to you!