Way Off Base

I sometimes miss the point when I'm writing an essay.
I did this again today.

We were given a topic, "What was the attitude of your parents or your friends when you decided to go to UVic?"
I started writing about my feeling when I decided to study abroad, then continued how I prepared, and then wrote about the attitude of my parents.

The first two, my feeling and the preparation were not being included on the topic. I realized about this after I wrote these, and thought "Oh, my gosh. I was way off base. But there is no time for rewriting whole of this. What do I do now..."

Then, what did I do? I wrote few sentences in the beginning of these spurious paragraphs, and made some kind of connection to the topic. But I'm sure that my teacher will notice it.
I have to make a plan more carefully before I actually start writing.