am I to old to start a plumbing carreer at 30
First find out all of the specifics. What is the placement rate from the school? Do you know how long you will have to work as an apprentice after graduation? What is the average starting rate and for how long? You will probably be the oldest student in the class and may or may not have the same opportunities for employment. This is not all inclusive list, talk to somone in the trade.
If you are satisfied and you think its doable, I say go for it.
What we've got here is... failure to communicate. Some men you just can't reach. So you get what we had here last week, which is the way he wants it... well, he gets it.