Celebrate ? Celebrate what ? Well, of course celebrate the fulfillment of your goal, your dream, whatever it may be ! Why now ? Because you need to feel the joy, the satisfaction of achieving it before it shows up in your 3D physical reality !
You need to raise your vibration to match your dream and maintain an elevated emotion to ensure its manifestation. You need to think of things that must be greater, better, happier than your present circumstances otherwise you tend to re-create your present reality day after day, month after month, year after year ! You see friends, that is the reason why poor remain poor.
So then, how to feel happier ? Friends, catch the celebration mood and remain in the celebration mode instead of the usual survival mode, to ensure the fruition of your dream. And guess what, it makes the journey to your goal, to your destination more enjoyable.
In any case manifesting a desire gives you a short lived sense of achievement. Soon you will be busy with your next goal, your next desire ! That is how our mind works.
So, it really is a good idea to always endeavor to enjoy the journey to your dream/goal by celebrating it NOW and feel happy now, before it is in our physical reality.
Let the celebration begin !