I don't think there are too many of us who haven't made some kind of mistake in a build. The trick is to not worry about it. Read the instructions, look at the parts, fit them together without gluing/cutting/whatever and think it through so it makes sense. {Measure twice, cut once} When you're sure about how it goes, complete the step.

The other thing to consider is that if this is your first plane that you will be flying, there is a chance it won't look great by the time you've learned. Build it well, but don't put so much into it that you'll be scared to fly it or be heartbroken if something breaks in a hard "landing".

If you're stuck, need advice or want to run something past us, we are usually a pleasant crowd.

If it's something unusual or not covered in the manual, it sometimes helps to post pictures.

Good luck!