Flying with a 2 year old

I am fairly new to the non rev travel scene and I have a 2 year old daughter, as well as two older children. When I travel non rev need to stay with my 2 yo but she has to have a seat. The older two can and will sit quietly by themselves. As I come from a small station in Alaska I am not sure of the proper way to inform gate agents that I need to be seated with my 2 year old if at all possible. Should I inform them when I get to the gate? Or wait patiently to be called up in proper order? I really hate to bother the gate agents but I want to make sure they know that I am traveling with a toddler. I have, in the past, just got our seat assignments and talked with the flight attendants on the plane to arrange for sitting us together.

I have looked at all of my airline policies and they do not address traveling with toddlers except to say choose wide open flights. Sometimes that is just not possible. (AKA - we like to visit family in ATL and there is only one flight a day to ATL in AS systems - that flight is NEVER "wide open")

So, what would others recommend? I can't wait til she is older and I do not need to worry about this anymore.

I would say to always approach the gate agent and let them know that you have a 2 year old. They don't really look at the age of the person traveling with you so they won't know until you tell them. In my view, this is helpful to them so they can, for example, ask you in advance if you are willing to separate in case there are fewer seats than nonrevs listed. Even now, when traveling alone, I still approach them when I first arrive at the gate to let them know that I am there and then I don't approach the agent again unless they call my name.