Now bitcoin price cross 11500$. i want to buy some bitcoin for long hold. Is it safe?

Hmm. I think this isn't the right time to buy bitcoin. Wait until it goes down again upto 6000 dollars because I think that is the current bitcoin's price limits when it goes down. After it reached the 6000 dollars cutoff. It will rise again as you can see now. The trend of bitcoin's price is going upward.