Half marathon training

I decided to join my cousins to run the Ottawa half Marathon on May 30th. As it turn out, my friend Sophie, brother-in-laws Scott and Mark will also be running with me!
The training has not been as difficult as I had expected. The Running Room group that I have joined in Kanata is not very fast. I think there are a number of people training for their first half. It's been a bit of a confidence builder.
At the same time, I have questioned a few of the Running Room methods for training. For example, I still can't figure out why practice runs are completed at a minute slower pace than you intend to complete the race. In other words, if you plan to run the race in a 5:55min/km pace, why train at a 6:55? The women I an running with don't really understand it either. None of us have completed the half marathon program through the Running Room, but the two other women have run a number of marathons and half-marathons. They seem to know what they are doing. They claim that if you want to run a half in 2 hours, then you need to train for that pace. Makes sense to me. All I am trying to do, is just keep up with these women each week. They are aiming for completing the half in under 2 hours. I don't think I can do that, but I would like to finish in 2:10.
Another question, why were some of the tempo runs at 4km and then on Wednesday we ran a 3km tempo? Is that all part of building speed and strength? I think the Running Room in Langley seemed to do things differently. Weren't we running further by this point in the schedule? Didn't we do hills by now?
My goal so far, is to enjoy the race and do my best in training. I am trying to watch what I eat before runs so that I don't have tummy problems half way through and I am very aware of how I am keeping myself hydrated.
My biggest frustration is trying to do my practice runs with Simon in the stroller and Baloo. Tonight, once Ian gets home from work, I plan to take a run by myself. 
I have been checking out a number of blogs from other runners and I realize that I will never be a serious about any sport as most other people. I will continue to run because I enjoy it, but I don't think I will ever find myself being competetive with anyone else other than me.