Calculated Risk

So, I posted something on my Tumblr acct that says: Your biggest risk will be the one you don't take.
Then, my sister told me, hey, I saw your post on Tumblr, do you know about calculated risk?
My mind was buffering...what an idiot, I thought of myself (sorry, been like this for a few weeks now, so please bear with me), then I said, no, no I don't. So she said, google it. And I did.

Definition:
Calculated Risk
noun
- A chance of failure, the probability of which is estimated before some action is undertaken.

Then, my sister told me (not the exact words, but to my understanding), there's nothing wrong in being a risk taker, but you must also need to weigh things before acting upon it.

And yes, I do agree.
The thing is, I'd like to take risks, its just that, with every decision I have to make, I calculate the risk over and over again, and concluding after that I'm going to fail at it, ending up taking a step backwards.

I don't know why I have always been afraid, was it because the wrong choices I made in the past? I don't know. Maybe because for once, I want to make things right. I feel like I screw things up more often than not.

Well, just gonna keep this short, need to prepare to meet my high school friends tonight.