I'm not sure about the law in Canada, but in the US, a contract with a minor is voidable by the minor but not by the adult. What this means is that the minor can cancel the contract at any time, although the minor may be responsible for items that are destroyed/used. A minor can make contracts for food/shelter and other necessities, but that wouldn't qualify here regarding web contracts. An adult can cosign, which seems to be the only way you'll "get around" this requirement. That's the law, at least as far as I understand it. Of note, when the minor reaches 18 the minor can ratify the contract, which is an affirmance of the contract as an adult.
Remember this -- the law is there to protect those that need protection. There really is no way to get around the age requirement other than having an adult sign with you. While it is obviously not the same thing, the law protects all those it deems requiring protection. To get around it would defeat the purpose, e.g. a mentally challenged person requires the signature of a custodian/conservator since they require protection.