Sketchup trial 21 with OS Sierra

Hello,
I just try the latest version of Sketchup, but it bug immediately with my laptop (macbook pro 13 ’ 2017 with 10.13.6
Is there any trial pro version under 21 available for my OS?
Thanx
Mark

You can trial 2019 as well during the 30 days.
Why not upgrade to a newer OS?

'cause I need to keep working with some soft which doesn’t work well with latest OS. I don’t find link to trial 2019.

www.sketchup/download/all