American Airlines problem...?

I am flying with American Airlines and on my way here, they did forget to transfer my suitcase and child's car seat so I had to wait on that. I did not complain. However, today I drive all the way to the airport and the guy is in the process of checking me in when I hear people talking about Dallas and I asked what was wrong with Dallas since I change flights there and he tells me my flight is severly late and I'll miss the other flight I was suppose to be on. I suppose he was just going to not tell me this big issue here until after he had my luggage and I'm SOL. Anyways... I had to rebook for tomorrow and the previous reservations I had it was just my daughter and I on a 2 seat row which is great because I get nervous on flights and hate sitting next to a stranger. This other flight, the first flight we are sitting next to a stranger which I'll settle for if I must, but they are not promising me a seat next to my 4 year once I change planes! Should I ask for 1st cl, what do I do?