Don't be rushed, be sure.
If you are not comortable to deal with an opponent 50 lbs heavier than you, there is something wrong with your Jiu Jitsu.
A 10,000 mile walk, begins with a single step and continues one step at a time.
If you believe, then you have already taken the first step towards your achievement.
Study is a life long pursuit.
Be positive and the challenge will be easier.