Invest in Bitcoin if you can afford it because at the end, you have very little chances of regretting your decision.
Indeed. If you believe of its potential then anytime you can buy Bitcoin as long as you can afford it and you understand the risk (since price correction is inevitable as well).
However, if you are careful and thinking wisely, a price dip is certainly a good timing to buy. Investors who used to seeing the price turning up and down knows when is the best time to fill our bags