Frog - Your statement "...it will be difficult"...fits the current state of the art as seen in the latest telomere research which reflects this difficulty, but the research goes further to indicate that it is not insurmountable...and that reversing the telomere decrease (extend aging) is the hot ticket right now... And the determination of "age" from DNA is not far behind...
Besides...your two statements..?
"...there is no way to determine age directly from the genome."
"Until (then)...it will be very difficult to use telomere length as an indicator of age."
Since you were such an active participant in the telomere discussion, I'm sure you know there is an Eternity of difference in your saying "no way" in one statement and "very difficult" in the other.
Telomere's ARE an exciting point of discussion tho, for DNAP's DNA Witness product and for our considering the possibilities of Immortality.... :>)
Take care,
Robert