I prefer to bring my Mac in Apple Store to update

You may find you can set up online appointments, within the US or

Canada; there are differences in how the Service/Support site works.

..From other nations or regions, these links may also perform as well..

• Apple Support - Topic Selection:

//getsupport.apple.com/topics

Link ^ was found by accessing Find Locations - Apple (US)

and Service/Support portal. Results changed from last year.

• Apple - Find Locations

(Sales; Service/support; Training/Cert; & Consulting.)

https://locate.apple.com/

Regional/Global (Other Nations, etc.)

• Apple - Find Locations - Location Selector

//locate.apple.com/findlocations

Another portal that may be easier or have a different pathway to same

content (selection & interface) could be the genius bar link; offers a lot.

(You may use these to set an appointment for services; that may include

a service center or that has no customer interface. Your product could

be sent to an industrial address, that you won't see. Or you may be able

to take the product in and drop it off; in Cue. The work orders get taken

in, per their timely arrival; and expected completion date.)

• Genius Bar Reservation and Apple Support Options - Apple

//www.apple.com/retail/geniusbar/

This portal divides the products by 'Software' // 'Hardware' sections.

And the interface, once you've gotten through to where you do it, can

be useful; insomuch as persons you could contact may use Chat, email,

or phone, etc. ~ One of these may or not be as direct. {..Confusion.?}

..An "independent Apple Authorized Service Provider"

may be able to give you more personalized attention..

(As Volunteers & not Apple Inc employees, there are layers

to this, that we collectively know "more &/or less" about.)

Why not call the GeorgeTown Apple Store and set your appointment for this upgrade process? Have proof of ownership, your identification, and a prior Time Machine backup before you go to the Apple Store. We are fellow users and Apple is not here.