All in? HELL NO, nobody should go all in, regardless of age. Taking higher risks when younger--that's all well and good. But going all-in on anything crypto is a recipe for bankruptcy. I wouldn't even allocate 20% to crypto. You'd have to be crazy to go even half-in, and I say that as a person who likes bitcoin. A lot. It's just way too risky.
Young should know what they want or goal in life,they can do bitcoin but they need to grow professionally on what path or career they wanted. Btc is good for financial.