German couple (60,55) want to rent a car in Florida - Is an IDP required and are there maximum age restrictions?

We rented a car in Chicago O'hare International airport this summer from Avis car. When we made a car rental booking from Germany, we received an email that German driver licence and an international driver licennce (for translation) would be required upon booking along with a credit card as a security deposit. We were also asked to present our German driver licence and international licence at car rental at airport, also they made a photo copy and returned those immediately and made an authorization on our credit card before lending the car.

Speaking as a citizen of Florida, the are three answers.

1. Yes you can drive with just your German licence provided it is valid. If you license has any restrictions on age or medical needs (like glasses) you have to comply with those. But, as a general rule, if you can drive in Germany you can drive here in the same license.
2. There are no age restrictions in Florida. There are "health" restrictions, but they are really just common sense. You must be able to see. You must not have a medical condition that would effect your driving (like frequently passing out). But that said, no one would know if you have an issue unless you volunteer it. There's no screening, or anything unless you get into an accident.
3. As for renting a car, you will need to check directly with the rental company. There is no law that says you can not. Only company policies. Most around here have no problem. Some may, specially smaller ones, but your "chain" ones like Avis, Enterprise, etc. Likely wont.

Good answers already. Just to add some personal experience since I got all three licenses: German, US and International.

1. I have driven with my German license in the US
2. I have driven with my US license in Germany
3. I have driven with either one in about a dozen other different countries
4. I have NEVER driven with or used my international license anywhere.

These days I pretty much use my US license exclusively simply because it's the smallest and easiest to carry around.

@Ali Awan already gave a comprehensive answer, but I would like to add this:

The credit-card like EU drivers license document indeed uses numbers to label the fields, but there also footnotes. I guess "Name" and "Vorname" can also be understood by non german speaking Americans, "Geburtsdatum" (date of birth) also is some kind of obvious. Together with your passport, it should be clear. Since the vehicle classes are labeled with pictograms, an American should be able to verify your EU drivers license.

*Should be*.

This german site states about the USA that

• most rental companies are quite relaxed about an EU license only, but some won't accept it.
• Kentucky, Georgia and Florida have a low tolerance to foreign drivers licenses
• Police in general has very low tolerance

Personally, I was in Illinois and didn't think about an international license, but the company didn't even ask. But since that site mentions Florida, I wouldn't risk it.

Further more, with your age, you still might have that large, gray drivers license document, which for sure will not be accepted. When you get the international drivers license, your old license will also be exchanged with the new EU document.

(I wrote about the international drivers license, but of course, this document is just a supplement, you'll need your original license document, too.)