Could i just pull my SSD out of my old computer and put it in an enclosure and use a USB a to c cable to connect it to my new computer?
If it has a removable sad drive, yes. I would go with at least a usb 3 for external use and if you don't plan on keeping the old one then you will have extra storage for travel.
Me personally will be pulling my 2008 HD and putting it in a external case to copy personal items since I plan to do a clean install of everything. Since it is 2TB i will keep it on me for a month or so to make sure I have everything then reformat and patron 1TB for Time Machine and 1TB for windows 10.
I have been swapping HD in my computer for years and it is really helpful using a HD vs flash drive.
The reason of the clean install is over the years I have updated and shaped out programs and it bogs down my computer. depending on how well you keep our computer organized it might be faster to go that way so you don't have a cluttered system.
A clean install is a term when you pretty much start from scratch. In my case I would install all the programs I use and re setup everything. After that I would copy my files over like documents, photos,music and movies. That is why i don't erase the original one incase I forget something