So, you have to consider whether you would accept any of the other programs over JHU - and how you would feel if you accept at JHU and then get into another program later. If JHU is your top choice, regardless of what other programs may say or offer you, then jump in. But if you aren't 100% sure, you still have time.
I just accepted my offer a few days ago, but remember you literally have until April 15th in most programs. Your spot is safe until then