Under current law, age no longer matters. If the property sold was your principal residence for at least two out of the last five years, then you can exclude from tax as much as $250,000 in gain (and $500,000 on a joint return).
Your age is irrelevant, and you can take the gain exclusion every two years if you qualify. By the same token, if your property appreciates by $250,000 to $500,000 every two years, give me a call. I could use your help in finding a new house.
If you owe the IRS money this could not be the case.