Question about compatibility of High Sierra (on MBP 2017) w Photoshop Elements 2018
It's not clear whether your concern is around the fact you're running macOS High Sierra or that you're using a 2017 MacBook Pro?

What I can tell you is that I've seen Photoshop Elements 2018 work just fine on Macs running macOS High Sierra. There really shouldn't be any issues, although everyone's system is different because of the software they have installed and external hardware that may be connected.

However, just in case you weren't aware, you can download a trial of Photoshop Elements 2018 to try it out first. I'd do that if you still have any concerns.