How scared should I be riding on a new tire? Right now it's only got about 3 miles on it but those 3 miles made me a little nervous. I know they have to break in but I'm just wondering if I'm overly sensitive to the new "feel" of the bike.

lift the rear and see if it tracks straight.
if it don't deflate it, pop the beads and reseat it.

Be wary... but every mile you ride is scrubbing your tire...
Don't panic,.. but just be aware...

I tie a bandana around my handlebars just to remind me that I have a new tire...
I accelerate just little more gently,... and slow just a little more when I'm turning into a 90' corner...
You are safer every mile,.. and after 20 or 30,... you can relax...
After 50 miles or so, you can start pushing the tire...

It's like a first date...
You've been there and done that,... but not with this one...

After 100 miles... you can start working off those chicken strips... ...

If it scares you,... just keep in mind that your old, dried out tires weren't up to the task either...
Depending on how tired your old your old tires were,... your new ones may be safer after just 10 or 20 miles...  They just don't realize their full potential until the release is worn off...
Once your new tire is broke in,... you have real grip...

Ok, thanks guys. Just checking.

It does track straight and the tire is seated correctly on the rim. I know 3 miles is virtually nothing to a new tire. It does have to break in. I might try "washing" the tire and see if I can remove some of the mold release that way.

Best way I know to break it in is to ride!