Al-Ghazali in the text, Deliverance from Error wrote:
- The physical sciences are a study of the world and it's stars; and of the sublunar simple bodies; such as water, air, earth and fire; and composite bodies such as animals, plants and minerals. They also study the causes of their changing and transformation and being mixed; this is like medicines study of the human body...
...and just as Islam doesn't require the repudiation of the science of medicine, it doesn't require the repudiation of the science of physics; except for certain questions we have mentioned in the Incoherence of the Philosophers
Turning to that text, we don't see that there is a specific mention of the rage of the universe, or indeed the world; and nor would naming an age would directly contradict it either.
Therefore, we can take the standard age of the universe, and the earth into account as it is judged by the sciences of astronomy - and this is roughly 15 billion years for the universe, and 4 billion years for the Earth.