Is younger really better?

Learning a language at any age is beneficial. Some studies have shown that:

The human brain is more open to linguistic development during the years between birth and pre- adolescence.
Children who learn a language before the onset of adolescence are more likely to develop native-like pronunciation

(Strozer, J.R. (1994). Language acquisition after puberty. Washington, DC: Georgetown University Press)

"When children get an early start to language instruction, they are able to achieve levels of fluency that has not been possible in the past due to the late onset of most language programs. Older children and adults can still be successful at learning a second language, although the level of attainment is less predictable because of factors that can influence language learning. Any exposure to a second language and culture is beneficial, even if native-like proficiency is not the goal or the outcome."

(Source :Age and the acquisition of English as a foreign language. Clevedon, England: Multilingual Matters.)