The fields at the first few races are pretty much 125 people. Even if you're last everyone is friendly and cheering you on.
I thought Granogue was a great first race last year as it was semi-technical with the turns and super early in the year. Plus it just wasn't really that far compared to some of the other races.
Nittany is a great race in the fact that it's so easy to figure everything out for your first time. It's an incredibly boring non-technical course that will beat the crap out of you if you have minimal fitness but I'll back @Heckler on saying it's a great first race.
Nittany has no confusion as far as parking, where to register, where to start, where to warmup, where to to spectate and find people, etc.