Updating from OS Mojave 10.14.6 to 11.17 or later in order to use SketchUp App

I'm using a MacBook Pro (Retina, 13", early 2015) with 16 GB of memory and a 1T hard drive. I'm wondering what the best way is to do the updating without messing up what I've already got. I've heard stories about various problems occurring when you update the software. Also, just to head off any comments about getting a new computer: (1) too expensive for me right now for me and (2) I love the various ports on this computer and I don't want to lose those.

Not so tech savvy here...

Thanks!

jen