Hi and welcome to the forum.
What spec machine are you using? (Processor, RAM, SSD, HD etc)?
When you downloaded the .iso, did you verify the SHA256 checksum against that published on the Zorin website. Methods of downloading Zorin OS - #8 by zabadabadoo
Also which application did you use to create your bootable pendrive. Users here tend to discourage use of Balena Etcher, but suggest others e.g. Unetbootin, Rufus.