My mother told me, I should establish credit at a young age.
Is there a adjective in this sentence?
Yes, there is one adjective.
These are the nouns:
mother
credit
age
One of those nouns has an adjective modifying it. Do you see it?
i know that establish and young are adverbs but i don't see the adjective
Oh, my goodness! You really need to study the parts of speech!!
http://www.ucalgary.ca/UofC/eduweb/grammar/index.htm
Click on Parts of Speech and study the sections on identifying verbs and adverbs and adjectives.
Then tell me which word in that sentence is an adjective.
Yes, there is an adjective in this sentence. The adjective in the sentence is "young".
To identify the adjective in a sentence, you can look for words that describe or modify nouns. In this sentence, the word "young" describes the noun "age", indicating that the mother is suggesting to establish credit at a young age.