I don't think there's any reason to feel silly.
This is my 2nd too and although I had a totally natural & very fast birth, I'm still a little nervous because, as everyone always says, each birth is different. There's absolutely no guarantee for me of another quick birth where I find the pain to be manageable.
I think it's normal & natural to be nervous. I even think it's good to be a bit flexible. I was dead-set against an epidural the first go round. DH & I had so many people scoffing at our NCB plans saying, "Whatever! You'll be begging for that epidural." It made me dig my super-stubborn heels in, determined to
prove them wrong. 
Obviously, that's not the reason I wanted an NCB, I chose it in the first place for a variety of reaons, but then after we shared our plans & got those reactions repeatedly, I became stubborn. I HATE being told, "You don't know what you're talking about."
Anyways, this time around I feel I have a healthier outlook. I do
expect a relatively quick, manageable birth, but if I end up laboring for hours & hours (like more than 30) & exhausted (like from a badly positioned babe), I'll go to the hospital for the epidural & the rest that may very well allow me to have a vaginal birth. Whereas I think with #1, if I would have had the epidural, I would have felt like I "caved" & I was a "failure" & they were all right, I was a stupid, clueless, naive silly child. (bear in mind, I was 31 YO when I had DS!

)
& that would have been a shame to feel that way! There's no reason to feel like a "failure" for getting an epidural, so it would have been a shame that it would have devastated me. In hindsight, I think it's a shame that I wasn't emotionally prepared to deal with an outcome that didn't match my ideal - if that makes sense.
I feel like I'm rambling, but I think my point is:
1. being nervous is healthy & natural
2. Planning for, working towards, and
expecting a good outcome is a good thing. (as we all know, approaching labor full of fear & anxiety is likely to be detrimental - leading to longer labors & worse pain.)
3. But be flexible anyway in knowing you simply can't control it, there are no guarantees & you'll do what you
need to if a need arises, such as transfer, epidural, CS, etc.

I used to think items 2 & 3 conflicted with one another. Kinda like going into a job interview thinking, "I'm awesome! They will love me. I will get this job." You NEED confidence to perform well in an interview. But don't let it crush you if you don't get the job. Expect the best - but except that it's not guaranteed.
I do still see how they conflict. But I think it's important to strive for both views.