You can hifz (Remember it by heart) Quran at any age. There is no age limit for it. But we all know that our memory is not very good once we grow up.

If you want to Hifz whole Quran or only some Surahs then do this while you are trying to remember it by heart. Every day do this once.

11 times Darood/Salavat

Surah Yusuf 1 time

11 times Darood/Salavat

Inshallah your brain will open up and will absorb Quran like a sponge.