Enforceability of non-compete clause

If  you compete with your former employer for 3 months, then you will need to pay liquidated damanges, though it's possible a court (if you were sued and it went to court) would reduce the amount as being excessive. However, the basic rule is that covenants not to compete are enforceable, especially when they are short in duration; and you signed a contract containing the clause, binding yourself to the terms.

Don't compete with your former employer for 3 months and, by what you quote above, you should not have to pay anything. The penalty is for competition after termination, not for being fired.

It's possible, although it might be unlikely.  There are several problems I see with this non-compete, and some of those might depend on which state's law governs the interpretation of the contract.

Most courts place some limits on non-compete clauses, because they interfere with a person's right to earn a living in their chosen line of work;  these clauses usually get interpreted narrowly, in favor of the former employee.  Here, it isn't entirely clear what the phrase, "not to compete with the company" means, unless there's more in the contract that explains it, so the entire thing might be too vague to enforce.

Other limits that the courts place on these clauses sometimes go to territorial coverage;  this one seems nationwide, which could be a problem although with something like internet hosting territorial limitations are pointless.  Duration is also looked at, and the 3-month period on this one would tend to make a court enforce it for that short time.

Liquidated damages clauses are also disfavored by courts, and some would refuse to enforce this unless there were some evidence that the $50,000 was actually a reasonable estimate of their real damages.