This is one you'd better get an attorney's opinion on in your locale, because the old company was clever. They did not get you to sign a traditional "non-comptete" prohibiting you from working in the same field within 30 miles, just a "pay us an outrageous sum ($104,000) if you do" agreement.
A pure non-compete is usually only valid if it is
1. reasonable in scope (for example 30 miles is a long way in many places, like a big city, but maybe not in a rural area), and
2. reasonable in duration (and 2 years seems too long for a job like this).
In some states if the agreement is too broad it is completely invalid; in others an overbroad restriction is only whittled back to a reasonable point.
This company used an outrageous "penalty" instead of a traditional non-compete. Will the Texas court interpret it the same way? I don't know. But you'd be wise to find out IN ADVANCE. It scares you and thus did its part. Now getting personal professional advice is another part of the cost of doing business, like buying a truck and equipment.
PS That you signd it as a condition to take that particular job is enough consideration in most places, and I doubt the court would be sympathetic to the claim that "had to sign it" to get the job as you could have gotten another job.
In order to be binding, a penalty clause such as this restriction against
