Is it required that I upgrade to Sierra

Forgive me for what is probably a very silly question, but I just got my first Mac. I used to use PCs with Ubuntu because my friends got me using it because I didn't like Windows 8.

I'm not strong with computers, I didn't like Ubuntu and all the problems that i needed a expert to help with so I went to Apple.

Now some of my friends are telling me I must upgrade to sierra while others are saying to wait. I like El Capitan because it's working well.

Do I have to upgrade? Is it required?

No, you are not required to upgrade to macOS 10.12, Sierra. While the upgrade is free, it is not compulsory.

Many, including myself, recommend waiting before upgrading. This additional time after a major macOS launch gives time for problems and regressions to be discovered.

You're indeed not required to upgrade to Sierra and you can run El Capitan for years. But the upgrade is preferable because the new version can include new functionality, bug fixes, improved security etc.

I have a bad experience with upgrading from Maverick to Yosemite (I upgraded as soon as possible), when the system was suddenly slower then before. It was better after few weeks when some updates were released. So my current strategy is to wait 2-3 months after the new Mac OS release until major problems are discovered and fixed, then upgrade.