Help me convince my parents to get me a Tumblr!

[wolfsquad]

Slightly agreeing with Skulleh here.
Yes, there's a side of Tumblr that's toxic and disgusting and there is NSFW content, HOWEVER: That's not the entirety of Tumblr. As Skulleh said, you can only see posts from the blogs you follow so follow people who'll post something that you'll want to see.
EX: If you want to see posts about  Tokyo Ghoul, then follow a blog that posts about that. If you want to see posts about dogs, then follow a blog that posts about that.

For another example. Me.
I like Black Butler, so I follow blogs that post about it and what they post are lovely fan-made images, fanfictions, headcannons, AU's, etc.
Then there are the problematic people that will send me hate because I support a certain ship, or because I don't ship something. What happens to them? I either make a witty or an intelligent reply and leave, don't respond to them, or I simply block them.

[toonanimals317]

Tumblr is a great website if you want to delve into Fandoms and perhaps cute animals, but even the Fandom pages can be... rather toxic. The owner of the page may post things you don't want to see, or don't want to hear. You just have to be careful.

May I ask how old you are? If you're at least 13 perhaps get a Facebook instead? It has a ton of safety features, and if you follow enough Fandom pages, for me it almost acts like a second tumblr, something I can scroll through.

Plus, no one can just follow you. So if you post something you only want friends to see, it isn't open to the world as long as your settings are right. You can follow what you want, and it's a good way to keep up with your friends who have it as well.

That's just my opinion though. I don't think you should join tumblr unless you're at least 15.