Youtube especially as of late has been having some pretty messed up tactics for targetted ads, using lots of hot words and ads that may appeal deeper to an audience of certain videos (If you look up owls for example you will start getting wildlife ads, or computers, then you will get ads for computer stuff/colleges. I feel it would be way more safe sadly, using youtube premium in order to avoid 3 ads before watching a 30 second video.
Please remember youtube premium costs real money. Please speak with a trusted adult before purchasing online.
Furthermore, like said below, there is a lot of content on youtube that is very adult, and may try to lure you in. When in doubt, use youtube kids, but be aware, that ads may still try to target you to click as much as possible