For the purposes of this questions, let's say I have a domain example.com. Eventually, I want to form Example LLC in California, where I live. However, at this point in time, I don't want to, because I'm not 18 and I'd prefer to do this on my own. Under California law, can I write a Terms of Service for my website (but where I don't sell anything) with Example instead of my name? The reason I ask this is because I understand you have to use your real name, establish an LLC/Corp, or file a DBA.
A Terms of Service is a type of contract, and contracts can only bind legal entities (persons, natural or artificial (e.g. a corporation)). So you can't have a contract binding the visitor to something that doesn't exist.
According to this, a DBA wouldn't help you either, because under the same rules of capacity as above, a DBA doesn't have legal capacity.
As always, for an answer you can count on, you should seek legal advice from a lawyer (which this is, and I am, not). You may also want to drop a line to Mark Bao, and see if he'd be willing to tell you about his experiences setting up companies as a minor.
Yes, you "can" write Terms of Service. The issue, then, will be how many problems you are creating:
Disclaimer: This post does not constitute legal advice and does not establish an attorney-client relationship.