Cryptocurrencies are hard to get your head around. I'll run through the main points now to save you watching all the dodgy YouTube videos out there.
Anyone can own cryptocurrency but to buy it, it's normal that markets ask that you are 18. The forms of holding cryptocurrencies can be broken down into a few areas, mainly relating to their security. All you need to know is before you can have access to your's you'll need a suitable exchange and wallet.
The exchange is where you as an individual can go to swap your cash for crypto. This is where you're given a price for how much you need to put forward in your earth cash in exchange for the weird space cash.
Exchanges are heavily monitored... they ask that you verify your ID and keep close tabs on where you're accessing your funds from.
Coinbase.com is the best for beginners.
A cryptocurrency wallet is where you funds are stored. This is an area of a computer that can hold the funds because of its access to the encryption and decryption key associated with the currency. Without the wallet, you wouldn't be able to hold and send your funds to their desired locations.
Sometimes signing up to an exchange can give you access to the market for purchasing the funds and also issue you with an online wallet to keep and store your purchased funds.
The key to all of this is your own personal security and anonymity. Cryptocurrencies are valuable. If someone learns of an individual holding a large amount, they may concentrate an attack to steal or have the funds re-routed into their own account. Because cryptocurrencies are sent virtually to a desired address, they can be stolen without any trace being left behind, so keep an eye on them!
It's all easier than you think, just have a play around and i'm sure you'll have some fun.