When you want to jump into a pool and are worried about the water being too cold, but you know that within seconds of you entering the water you will have acclimatised to the temperature, but you continue to procrastinate anyway.
What you're actually worrying about is the shock effect of transition you will experience when entering the cold water. Remember though that the transition is temporary, it can't hurt you and promises what you want on the other side of the temporary effects of transition.
Procrastinating by the pool, you will have a dozen voices in your head saying "don't do it, the water is cold", and a dozen voices saying "do it, the water's lovely!" - so which of the voices do you listen to? Listen to the "do it!" voices, because if you jump in and don't like it, you can jump out again having tried it. You will have gained valuable knowledge, experience, growth and development from the exploration, even if it's not something you wish to continue with.
Conversely, there is simply no growth in listening to the "don't do it" voices, as this choice will lead only to stagnation, boredom, frustration and angst. Regret the things you did do in life, not the things you didn't even suit up for - but more importantly, life is too short for regrets. Everything is sent to us as a lesson.
Life is for living, dreams are for chasing, listen to the "do it!" voices and live your life huge. Start now.