Hello, a couple days ago I built, tensioned, and trued a wheel for the first time. I thought I'd followed Sheldon Brown's instructions to a T. I did a simple 3-cross pattern, with a mavic cxp22 rim, dt spokes, and my old shimano 105 hub (32h). I did all this, and when I finally put the wheel on I realized...I'd laced one side differently than the other...I'd apparently laced one side backward, with the leading spoke crossing over the trailing spoke rather than under. It looked just like the example when I first finished, in terms of pattern. It being my first wheelbuild I was somewhat proud of myself for getting it done. Now, being the perfectionist and worrier that I am, will this cause major problems? I needed the bike up and running (it's my do-everything ride) so I put on the tire and went to class. I've ridden it maybe 10 miles so far and it's stayed true. Should I take it apart and relace it?

You mean leading (or trailing) spokes are inside on one side of the hub and outside on the other? If that's the case, no problem at all.

Maybe. What it looks like is that one one side, the leading spoke goes under the third trailing spoke it crosses. On the other side, the leading spoke goes over it.

Asymetrical laceing.

Many factory wheels used to be built that way. Some wheelbuilders still build wheels that way on purpose. Esthetics aside, it's a zero on the things-to-worry-about scale.

Dont worry, should be OK. Wheels acn be built with both sides looking the same from the same side or as a mirror to each side.
Well done by the way!

+1. I prefer mirror spoking but it's just for looks. I do like symmetry. Ride on!