I think that it's quite safe to invest in Bitcoin now but I will suggest that you buy at intervals, also It is good to understand the wallets before investing. This is not just to Bitcoin but all investments.
Like buying on monthly basis or per year. I think this depends on the person because some who has analysis will buy one time in a dip because when you bought it on right time you can get profit than buying in intervals but only if you have enough money to buy but if you are lacking money then it is good only when you have money