Thank you! Just what we needed!
"9,1" is non-Retina which is good. You can access its innards rather easily for at-home servicing, like cleaning, adding RAM, or upgrading to a solid state drive (SSD).
The i7 processor was the best available at the time. Mine is a lowly i5 2.5Ghz and it has no issues. If mine runs 10.13 well, yours should do better.
With 8GB RAM you are probably OK with Chrome if you are willing to accept its gluttonous behavior. I would consider quitting it after use when possible so its many minions still running in the background don't interfere with other apps.
A snapshot of your current figuration will help us judge if you have anything installed that could interfere with a newer OS version and also see if your RAM is sufficient and if your hard drive is reasonably healthy. Fortunately there is a safe and secure way to do that.
A respected and long-serving member of these communities has created a simple utility that will take that "snapshot" of your configuration without revealing any sensitive information about you and your computer. It only runs when you tell it to, not in the background, and therefore creates no performance penalties. It is Etrecheck, and is available here:
http://etrecheck.com/
Run it and, when its results display, select "Report" from the left-hand pane (scroll down), then click Etrecheck's "Share Report" icon followed by "Copy Report" from the resulting dropdown. Paste the entire report into a response to your own thread here. It will allow us to see if anything needs addressing before attempting an upgrade. Failed upgrades are too often caused by software incompatibilities, especially with useless products like anti-virus and so-called cleaning apps. Out-of-date browser extensions/add-ons may also hinder a successful upgrade.
