Leave crocs alone! They're just a footwear.

Halp

Hey, do what you want. Consider these questions:
How much time do you want to put into tumblr?
Do you have the time?
Would it serve as too big of a distraction to your normal life?
And if your age is a bit on the young side, don't tell them your age!

Tumblr doesn't take kindly to twelve year olds or lower but other than that you should be fine.

By the sounds of it, I should be good.