This is a "unibody" MBP, is that assumption correct?
If so, you CAN upgrade it.
You can replace the internal platter-based hard drive with a 2.5" SSD.
You could also upgrade the RAM inside, although 8gb is probably "enough" unless YOU KNOW that you "need more". I'd leave it at 8 for now.
Go to ifixit.com to see what's involved in swapping the drive.
IT'S
EASY (shouting intentional). Hardest part is taking out all the screws on the back and putting them back in.
You do need THE RIGHT TOOLS FOR THE JOB:
- Phillips #00 driver
- TORX T-6 driver (for the "nubs" on the side of the drive)
Just about any 2.5" SSD will do.
DO NOT "buy the fastest" -- will be of no importance.
Instead, buy "for price" (I like Crucial and Sandisk).
You might also consider buying a USB3 2.5" external enclosure, like this:
SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)
tinyurl.com
You can use this to "prepare and test" the SSD BEFORE you open the MBP.
That way, you will still have a "working Mac" while you do the prep.
And... after you do the drive swap... you can put the old HDD into the enclosure and use it for a backup, or extra storage.