Is it against the law in the United States for a car rental place to allow a person under 25 years of age to rent a Full Size SUV?

Is it against the law in the United States of America for a car rental place (such as Hertz, Enterprise, or Budget Car Rental) to allow a person under 25 years of age to rent a Full Size SUV?
I'm renting a brand new three-row Full Size Ford Expedition in Los Angeles, California.
I'm 22 years old.
I have a credit card & have tried to make reservations online in advance, but worried I'm going to get denied at the Enterprise rental car desk once they see my I.D. Or something…
am i too young? Is it against the law in the United States for a car rental place to allow a person under 25 years of age to rent a Full Size SUV

The age restrictions are from the rental car companies, not state or federal law.
The rental car company might have a rule that certain people can't rent certain cars based on age.

Have you rented a car before? Unless you have already picked up the car, you don't know what car you are renting until you pick it up. When you select a car online, you select the class of car you want, not the specific car. The website will give an example of a car from that class. Based on the picture you have shown us, you are renting a Full size SUV which according to the Enterprise website would be a "Ford Expedition or similar". This could be the Expedition, a Toyota Sequoia, Nissan Armada, Chevy Tahoe, etc. Also you have no idea how old or new it is until you take possession of the car. From Enterprise, it's not uncommon to get cars with over 30,000 miles on them.

There are no laws addressing that. If you had actually looked on the enterprise website, which I doubt, you would have noticed a place where you can select your age, which means they do rent to under 25. You will also notice that it will cost you twice as much as those over 25

Here is Enterprise's policy:

The minimum age to rent a vehicle is 21 years of age. There's no maximum restriction in the United States and Canada. See Exceptions below.

A 'Young Renter Fee' may be applied to your rental, if you are between the ages of 21 and 24.
The average cost is approximately $20.00 per day but can be higher or lower based on the rental location.
If you wish to know the cost of the 'Young Renter Fee' you may begin the reservation process to determine the exact amount of the fee for the rental location (please remember you will have the option to confirm or cancel the reservation).
Renters 21 through 24 years of age may be restricted to specific car classes.

It's not against the law but most rental companies have made a business decision not to rent to those under 25.
This is based on insurance companies refusing to offer cover

Yes, but not against the law the way you're thinking.

The law in every state (and territory, and province) says you must have the owner's consent to drive their vehicle, no exceptions. If the owner (be it a rental company or an individual) doesn't give a person consent, that person can't legally drive that vehicle at all. Some jurisdictions have different charges for driving without consent, but where I live it's just plain theft.

If the owner (including rental companies) says nobody under __ years old can drive their vehicles, that's the owner's decision and the law is on their side. No other laws are needed.

If you can find a rental company who will let you drive one of their vehicles, you can drive that vehicle. When calling around for prices, you definitely want to let them know your age.

No, but each rental place can set rules as to who can rent or drive their vehicles, and most do not allow anyone under age 25 to rent or drive them.

It's not law, but because of insurance issues you must be 25. There are a few rental agencies ( smaller independent agencies) that will rent under 25. You will be turned away, even with the reservation, even if the folks rent, you ( under 25) can't drive, violation of contract.

No. In fact, in New York and Michigan the state laws require them to rent to 18 year olds, although there can be a premium for that. Alamo rents to 18 year olds across the US.

No, it's not against the law. The 25 year minimum age is an insurance limitation.

There's no law but most major rental companies refuse to rent to those under 25, does not matter if its a Full Size SUV or a small economy car.
The reason for this is liability as under 25 statistically have the most accidents
There are a couple of states that require them to rent to under 25s but they make their insurance mandatory and the already high premiums are higher because the driver is under 25