Some years ago I mined BitCoin and used Armory as my wallet. Now however, I only have my paper backup but unfortunately my Mac refuses to open the program. I tried to install a virtual machine and after a lot of work I managed to open Armory, but then the program was offline, and I could not retrieve any information than what I already had. After searching around I figured out that I have to download the entire blockchain (100GB+) for it to work, but that will not work for me.
So my question is:
1. Is there any way for me to check my balance without downloading the entire blockchain?
2. Can I transfer my balance to an online wallet?
3. Does anyone know how to open Armory on High Sierra?
Any answers will be highly appreciated

What do you mean by a paper backup? Do you have your private key? If you do you can use some light client, which does not require you to download and sync the blockchain, and just import your keys to it.
Eg. Electrum is a good choice.
Once you have your private keys, you can transfer your coins anywhere you want to.