Mac newbie looking to buy cubase need help

It’s been a year since I’ve been able to record. Been saving up for new gear.
Ive got my hands on an iMac with an i5 processor 8 gigs of ram. Pretty sure that should be enough juice for my needs.
A focusrite scarlet 6i60 is on its way in the mail.

Im almost ready!!!

Now I just need to buy a copy of cubase. Looked at all the versions and figured buying cubase artist would be the best choice for me.

So Im totally new to mac. I have only used pc up until this point. I see my current os is OS X Lion 10.7.5
Looking that Cubase Artist 8.5 it says I need to have Os X 10.10/10.11 I think.
If I buy 8.5 will it install on my OS? Do I need to update the OS? I just got it from the shop. They formatted it for me two days ago. I figure it should be updated. Do I just not know how to read OS versions on Mac?
I feel kinda dumb for asking about this but the truth is, when it comes to mac I know pretty much nothing. This computer will be used pretty much exclusively for recording.
I just don’t want to drop the cash on cubase and not be able to use it.
Would appreciate any advice/knowledge
Thanks for your time.