I've signed up for this too! There aren't many half marathons in London so if you do live here then once the travel costs are taken into account it's a decent comparison. I paid £26 to get into the Brighton Half and then trainfare on top of that.
I hope it's going to grow into a regular event for years to come!
13.49 on my Garmin too. I knew something was up by mile 5.
I got a pb but it's galling all the same as when I checked my data I would have taken 3 mins off my time. It also lessened my enjoyment going round as I was wondering what had happened and how long it would be by the end, was my pacing right etc.
See how it goes and, while it's great to have a goal, don't make getting back to running another pressure for yourself in the first few weeks and months post-baby. You may get back to it all in weeks or it may take longer.
Even if you don't breastfeed, it can take a long time for hormone levels to settle down and that can have a big effect on your ligaments and also your core strength (especially pelvic floor).
I have had two children who are now 2 and 4 and it's only been in the past year that I have properly got back to running. Now that's me, it may not be the same for you but be gentle on yourself. The flip side is I am now running further and faster than I ever did pre-kids so don't worry if you can't get back to it straight away, you can pick it back up again further down the line.
Oh and do your pelvic floor exercises like a demon!!