Investing 30k in Bit for Kid's College

My dad just retired and sold his home and, very generously, gave me 50k. He suggested to put 30k in Bit Coin for my children's college. I have 2 toddlers ages 2.5 and 1. I put 10k in Bit back in October and it's done extraordinarily well. When I went to buy yesterday I see it hit a peak.

Do I buy at current price of 66k or wait for it to drop to 62ish? Will it drop again? Should I wait for 50s? OR because the purpose of this money is for a college fund, would the difference in price not matter as much in 17/18 years?

Open to all suggestions. FYI, just diversified 10k spread out among 10 other coins, 1k each. Thanks in advance.