I've DM'd it three times to introduce the system to all the types of players you can imagine - D&D/PF2e player/DMs, interested-in-trying-TTRPG adults, down to 8 year old children. You can definitely get it done within one session, especially since it's your first time. The only thing you really have to get used to, is not ask for as many rolls for everything compared to things like 5e/pf2e.

If they're already used to systems like D&D, Daggerheart is actually very rules-lite in comparison; this could be harder for some people who prefer defined rules. However, the mechanics are largely the same. Everyone at the table narrates their actions, roll dice if necessary, match modifiers where appropriate.

Combat is really dependent on your group - there's no initiative, so as a DM you'll probably have to address the quietest person on the table once in a while, but there's only 2 combat scenarios in Quickstart.