The challenge with topics like this is to make a non-cliche essay out of a cliche topic. What really matters is the presentation - the essay needs to be both well-written and attention-grabbing. Have people read it; if you find it's a good essay, go with it.
It's the dead grandparent that is the usual cliche. Students sometimes search for some personal tragedy to write about. And for many 17 year olds the only significant tragedy they have ever experienced is the death of a grandparent.
Unless you can come up with some truly unique angle or insight, I'd stay away from the dead grandparent essay.