How many ages are there?

In the past:

Col 1:26 the secret that hath been hid from the ages and from the generations, but now was manifested to his saints, (YLT)

Ages denotes a minimum of two. So there is at least two ages in the past.

In the present:

Gal 1:4 who did give himself for our sins, that he might deliver us out of the present evil age, according to the will of God even our Father, (YLT)

Age singular denotes only one age.

In the future:

Eph 2:7 that He might show, in the ages that are coming, the exceeding riches of His grace in kindness toward us in Christ Jesus, (YLT)

Ages denotes a minimum of two.

We can say then, there is a minimum of five ages which the Scriptures teach.