I made peace with the fact I definitely hadn’t done anywhere near enough training to try and run a pb (I’d probably managed 6 weeks, and no more than 3 runs a week at best – i.e. not much/enough). So I just took my time and enjoyed it. For the first time ever I didn’t have any “bad bits” and had a massive grin on my face for most of the course (as opposed the usual grimace).
If you’re thinking about doing a marathon I’d totally recommend Berlin, flat, really well-organised, great crowds. Plus Berlin is a really ace city.