I think Bitcoin will pullback. With it constantly breaking ATH, the price is not too stable. But how much it's going to pullback is upto the people.
Bitcoin might reach to $8000 before pulling back to $5000 and then double again to $10,000 by the end of the year.
Bitcoin will grow even bigger in 2018. I do think now is the best time to pickup alt coins. They are undervalued in compared to btc.