I have Macbook pro 2011, 13 inch, i5, 4gb ram, High Sierra. Can I update it to mojave? I am actually afraid that it might kill my mac.

Did you, in fact, mean Monterey, as Mojave is an old version? The question is rhetorical, anyway, as neither version will run on your Mac. Mojave (and subsequent versions) require a GPU which is capable of supporting Metal (https://en.wikipedia.org/wiki/Metal_(API)), and these were introduced in 2012. The most recent version of MacOS your MacBook Pro can run is High Sierra (10.13).

Attempting to install a more recent version wouldn't harm your computer, as the install would simply fail at the 'checking hardware' stage.

User wrote " Can someone assure me that my mac will not be broken after updating high sierra to mojave with my mac specifications."

Reply " The computer MBP 2011 does Not Qualify for this upgrade. " So of one were to attempt the YouTube method, one may very will perform exactly would you do not what to happen " be broken "

The computer MBP 2011 does Not Qualify for this upgrade..

So, no worries able killing this machine.

macOS Mojave - Technical Specifications

General Requirements

• OS X 10.8 or later
• 2GB of memory
• 12.5GB of available storage (OS X El Capitan 10.11.5 or later)*
• Some features require an Apple ID; terms apply.
• Some features require a compatible Internet service provider; fees may apply.

Mac Hardware Requirements

For details about your Mac model, click the Apple icon at the top left of your screen and choose About This Mac. These Mac models are compatible with macOS Mojave:

• MacBook (Early 2015 or newer)
• MacBook Air (Mid 2012 or newer)
• MacBook Pro (Mid 2012 or newer)
• Mac mini (Late 2012 or newer)
• iMac (Late 2012 or newer)
• iMac Pro (2017)
• Mac Pro (Late 2013; Mid 2010 and Mid 2012 models with recommended Metal-capable graphics cards)

"Thank you. But I watched something in youtube wherein they had to go through recovery mode etc to have the update mojave. I think I can follow that but yeah I'm afraid still haha"

Mojave is not possible, and it will not work whatever you do.