Acts 13:36a
If you're still alive you still have a purpose given to you by God. I think most of the time we don't even understand what that purpose is. Probably when we think we know what our purpose is we'll probably a bit off base.
It's best to just do what is set before us, do what we know God is calling us to do and leave the results to Him.
You are vital to God's plan. Vital.