Iphone 4

My iphone 4 has been having problems while typing and the apps keep crashing. It's incredibly slow and takes forever to load pages. It's the white model A1332 and it has 16 GB. It runs ios7.1.2 and it has never been jail broken. I'm wondering whether it's the phone or just it's age. Is anybody else having the same problem?

ive found no fixes for this please help me