is it really worth it?

If I were you this is exactly what I'd do. Put the inheritance up let it make some money for you. Go through school, get your training in. Work 1-2 years for a company, keep a record of ALL the expense that you know about on your truck, you'll have to estimate on some of them like the payments and insurance etc.

Since fleets don't pay the same price for equipment that an owner operator does figure $2000.00 for the truck payment and $1,400.00 for the trailer (reefer) $750.00 month for the insurance on the truck and trailer. Double the deductions that the company takes out each week on your check for FICA, SS etc taxes, multiply that by 4 to get the monthly rate because as an owner operator you pay it all $ 45.84 per month for the 2290 tax, W/C is harder to figure as it's based on total payroll and you won't know that. so take your gross, multiply by .18% to get an idea of what you'll pay for that if you're going to have it. Then add another $350.00 for health insurance. Use what ever you're getting paid by the company for your paycheck because you pay yourself driver wages. Average the road use tax out to $50.00 per month. Truck tag average around $125.00 per month, trailer around $10.00 per month depending on where you tag it at. Take .10 cents per mile cost on the truck and .5 cents per mile on the trailer for equipment replacement cost.
Then with the other expenses you are keeping up with you'll see about how much it cost to run the truck.