In regards to seeking knowledge. If a person begins seeking knowledge in a later age like at 18 years old, then is it better for him to complete the memorisation of the Qur’aan then begin the other sciences like the instrumental sciences or what? We hope for some elaboration?
If the intent in seeking knowledge is the knowledge that is communal, that is, he has gained knowledge of what will correct his Aqeedah, his worship, his behaviour, however he did not expand in that and he wants to expand in it and it is knowledge that is a communal obligation and not an individual obligation, then we say: he chooses between continuing in memorising the Qur’aan because it is also a communal obligation or seeking knowledge. Even if he started seeking knowledge later as you mentioned in the question. Verily in the likes of this, his innate preparedness is observed. Perhaps [some] students of knowledge have an innate preparedness to memorize and not an innate preparedness to understand the legislated rulings and preserving them and memorizing them. So then with the condition which has been clarified before; if he gained knowledge that is an individual obligation, then he chooses to seek knowledge even in a later age or to continue to memorize the Qur’aan and have concern for it”
[Silsilatul Huda wan Nur no. 729]
Faisal Ibn Abdul Qaadir Ibn Hassan