You should not invest it at all because why should you, with holding it for a long term you can maybe become a rich man.
Because if you invest those coins you can get significant returns and when compounded with the rise in price of bitcoin it will allow you to get even more profit even faster, those that are holding but don't have many coins will have to wait for a massive rise in price.
Nothing can ensure that you will be rich with investing. There are many possibilities that you will lose all the Bitcoin you have after incesting. Being wise and smart are very important. if you have these factors, you cab reduce the loss and increase your profit after joining a potential project. However, risk is always there so be careful. You will cry after losing all 12 bitcoin
You are talking about the worst case scenario and to lose those 12 coins you will need to invest in scams, which are not investments or being the worst investor ever, if you don't have an instinct for businesses then leave your coins sitting in your wallet but even some of the safest investments could give you 3% a year.