Yeah, what you did was not smart. If you're being pulled over for a minor traffic infraction and you already know that you're guilty, simply admitting to it is usually the best option. I've gotten out of many tickets this way, because cops really do appreciate when you're not trying to BS them.

I was also pulled over once and accused of running a stop sign that I knew I didn't run, because I had seen the cop sitting there as I pulled up to the stop sign and made extra sure to completely stop. Due to the time of day, I believe he was (illegally) fishing for a DUI stop, and had considered filing a complaint with the department but never did.