You are not too old to study and pass it. You are not to old to pass TOEFL. You are not too old to apply, be accepted and graduate from International program. But: you might be too old to acquire a significant debt
Before making a decision on spending money on the IDP process answer some of the questions:
1. Will I have enough time to prepare for exams with work, children and other adult responsibilities. Because to graduate before turning 50 will require you to be very efficient, meaning passing exam first attempt
2. Am I able to get all the recommendation letters for application. All the letters now have to be uploaded online
3. Do I have money to pay for the program. Keep in mind, that programs prefer young recent graduates, meaning you will not be competitive for cheap state schools and will have to pay high tuition of a private school. Do you have $300K on average right now in your pocket?
A lot of people think only about projected salary/income often forgetting about taxes and loan repayment costs. Figure out if you will be willing to work at a public facility for 5-10 years to have your loan forgiven. Do you want to choose income based repayment and pay a huge tax on 300K at the age 65? Simple calculations: dentist salary in your area, minus taxes, minus loan repayment. What would be left for living expenses and retirement savings?
4. Am I up to all the stress?
5. Am I in good enough health to get disability insurance when I graduate? Because you don't want to have a huge loan and not be able to pay it off
In order to do all the fast and smooth transition to licensed dentistry you need to have time, money and very supportive family. Yes, all three
Otherwise it will be long and exhausting
There is a fairly easy way to provide well for yourself and family. Do the dental hygiene. Private schools like Concord college offer fast 17 months program, practically no requirements and much cheaper
You may have guaranteed good income and no headache