Dungeons and Dragons

I've always been interested in trying the game, but didn't know anyone who could DM. I became really interested in playing a few months ago, and decided, fuck it, I'll do it myself. I just ran Dragons of Stormwreck Isle last night with a few friends, all of us completely brand new to D&D. I hit one snag where a player was prying for more information about Varnoth's history. They rolled really well, and Varnoth isn't necessarily guarded about her past, but I had NOTHING more to give them. The module had no more history, and I don't know the world well, so just trying to make up some lore on my feet was really difficult. I tried to give more jargon, didn't sound great, and just ended up making her tell the player that there wasn't much more to say, and that she'd moved on from that time in her life. This stuck out to me as a failure on my part, but after the session, I told the player about how it looked from my end and they didn't seem to have noticed that I was fumbling. They just assumed I had everything out in front of me. So I guess the improv was decent enough, and least for my completely inexperienced players. Anyone have tips on what to do when a player wants more information that an NPC should know, but it isn't something you'd prepared for?

I'll have to learn the rules a little better (the first encounter with the zombies featured 5 minutes of me leafing through the PHB because I ran into an important mechanic I didn't quite understand), and I should probably prep the story a little better too, but I'm beyond pleased at how successful the session was. Everyone had a great time and wants to keep playing. It was a ton of fun improvising and creating a fun goofy story together with my buds. Just very happy to have this new fun creative thing to do with my friends and want to share that joy. I'd really like to create my own stories eventually, but it does seem very daunting.

Anyway, thanks so much for all of your help! Reading through posts in this community has been invaluable to learning how to play and DM.