Moving violation..NASA form?

I recently got my PPL and went for my first x-country with my wife.

I trained at an uncontrolled field and going to a controlled field always
was a little more challenging for me. Anyway all went well on our trip to
the class-D airport. We got the courtesy car, went to have the $100
hamburger..all in all it went great!

On our return trip however, I screwed up. This particular airport does not
have a separate ground frequency..tower is also the ground controller. After
I started up the plane, for some very stupid reason I assumed that since
there is no separate ground controller, I did not need permission to taxi to
the active (I know, its unbelievably stupid!). I tuned ATIS, figured out the
active, tuned to tower and without saying anything, I started to taxi to it.
I was not going to get onto the runway or cross any runwyas and would have
definetly asked permission but did not ask for taxi clearance.

The tower called me and told me to "STOP". I hit the brakes and responded to
their call. They asked me what I was doing. I sheepishly said I am taxing to
active. The guy tells me its a controlled field and I am required to ask
permission before I can taxi. I acknowledged. He asked where I was headed
and I told him. He cleared me to taxi to the runway.

While getting to the active, I came across another runway that was closed,
but since the guy had chewed me out before I decided to ask anyway. He told
me I had already crossed the hold-short line so yeah go ahead! I taxi all
the way to the active, he cleared me to depart and go to my heading.

Now I know I screwed up with not asking for taxi clearance but I believe I
did not need his permission to cross the other runway since 1, it was
closed, and 2, he had cleared me to taxi to the active which means I can
cross any runways on the way!

Anyway, he never asked me to "call the tower" or anything. I am wondering if
I am in trouble? Should I file that nasa form? I talked to my instructor and
was told it was no big deal since they never asked me to call the tower and
did not mention any action would be taken, but I still concerned.

Should I be worried? Others been in this situation?

thanks.

PS: posted this in the student newgroup too so others can learn. When in ANY
DOUBT, ASK!