When is "ready" ready?

The age old question---Am I ready to be a parent? I have been wondering about this for about 5-7 years now. I see babies and feel such a pull but, at the same time, is that really enough? Does that mean I should try to get pregnant? For all I know, the question could be purely academic. Maybe I wouldn't be able to conceive so easily.......I am 34 now and the clock is ticking very loudly. However, as a teacher, I see kids who are impossible, have a million problems, and are very unpleasant to be around. Honestly, only about 2% of the school population but it makes me worry.....would my kid be like that?
As a woman these days, I do feel blessed to have choices. There was a time when birth control was very inaccessible and it was much more socially unacceptable to not have given birth by this time in my life. Also, I have a wonderful husband who would be more than willing to share responsibilities, but it is so hard to make the jump. How do you know for sure that this is the right decision? Don't some parents feel regret at going down this road? I have never heard anyone vocalize this but it seems natural that someone would feel this way when faced with a really difficult child. Any advice? Words of wisdom? How did you know before jumping?