I don't think you went too far. Sometimes, there comes a point where something must be said. Your wife is the victim of a cult. As a husband and Father, I understand where you are coming from. Usually we bottle things up, thinking that NOT confronting the situation will promote peace in the home. Well, peace is not just the absence of war. You cannot have true peace in the home if you and your wife have an uneasy truce that erupts into a conflict at regular intervals.
I think you were correct to speak out. Perhaps you said something the wrong way, or could have worded it better? Who knows? Sometimes people need a bitch-slap of truth. You must get them to confront reality. The WTBTS is saying that everything that you have done with regards to education is demon inspired. Had you only went to school for 3, not 4 years, you would have been ok. They are self-righteous Pharisees who have no clue what it takes to provide for a family. They live off of the labor of others. Not one of them would dare get a job and support their ministry like the 1st century Christians.
I think you should:
1) Tell your wife that you love her no matter what. [ unconditional love is what she really needs and does NOT get from the ORG.] That REAL love may be what wakes her up.
2) If the problem persists, go to JWfacts or other places. Get your thoughts in order. invite the Elders over and respectfully confront them on the subject of higher education. Take it to them. The burden of proof is on them, which they cannot provide. Make it clear that YOUR job pays for the party. Ask them if they want to financially support your wife's pioneering or service. They will more than likely refuse to meet, or constantly contradict themselves during the meeting. Either way, this will be an awesome witness for your child and your wife. It's YOUR HOUSE BRO!!
That's my 2 cents. I think you did the right thing. Sure, it wasn't easy and feelings got hurt, but it will get easier.