Which one is older between Prakrit and Sanskrit?

 People are confusing.

1.The term “Prakrit” is coined in which language?

In Sanskrit.

The Sanskrit categories any language other than Sanskrit as Prakrit.

#It is like putting boundaries. Manusmriti is applicable South of Himalayas and North of Vindhyas. Suppose if there is any confusion in Varna of a King in South, say Shivaji, it simply put him as Sudra instead of Kshatriya. Technically, he is out of geographic boundary.

#It is like in all Tamil literature mention of any language as “Vada Mozhi” meaning language of North. It is putting all languages other than Tamil as “Vada Mozhi” But many interprete as Sanskrit , it may not be so.

2. The mention of Prakrit in Sanskrit become prominent when it faced competition from other languages given prominance by new found religions in 4th to 7th Century. It categories each and every languages under the umbrella term Prakrit.

Conclusion: Prakrit is a general term used to represent any language other than Sanskrit during 4the to 7 the century.