Exciting, getting closer!!
Just to give you some time to consider it, you can extend the life of your plaster with a good/great startup, but if you want to preserve warranty, you may have to do what the PB says, or be prepared to fake it behind his back. Here's some reading, not to push you into it, but just so you know the full picture on plaster start-up.
Pool School - Start-up New Plaster
A Bicarb Start-up guide for TFP members
The Bicarb Start-up and Why it Works
Like most things "pool", you're likely to hear that anyone on the internet is full of crud, and they've been doing it for years, yada yada. That said, some members here have had success by providing the info to their PB and talking it over.
At the very least, find the startup directions for the product you're using, because some PBs really push the envelope on getting in and out.
And no matter what they or you do after, if the plaster is well applied, you'll get many years out of it. To put it in perspective, if plaster is well applied in the first place, you're likely to get 10-15 years out of it (maybe more / maybe less) even if they do the worst startup. It might not be as smooth as the best startup, but still totally fine for swimming and playing. With the best startup, you can add 3 to 5 years to it's life, and with good water chemistry after, a few more years and it will remain as smooth as new for a very long time. Can't predict with certainty, but hopefully that puts it into perspective.