am i too young for further school?

Ｈｉ　ｅｖｅｒｙｏｎｅ．　Ｉ＇ｍ　ａ　ｔｗｅｎｔｙ　ｆｏｕｒ　ｙｅａｒ　ｏｌｄ　ａｎｄ　Ｉ　ｊｕｓｔ　ｆｉｎｉｓｈｅｄ　ｃｏｌｌｅｇｅ　ｗｉｔ ｈ　ａ　ｄｅｇｒｅｅ　ｉｎ　ｂｉｏｃｈｅｍｉｓｔｒｙ．　Ｉ　ｗａｎｔｅｄ　ｔｏ　ｇｅｔ　ｉｎｔｏ　ｇｒａｄｕａｔｅ　ｓｃｈｏｏｌ　ｂｕｔ　Ｉ　 ｄｉｄｎ＇ｔ　ｇｅｔ　ｉｎ．　Ｉ　ｗａｓ　ｔｈｉｎｋｉｎｇ　ｏｆ　ｗｏｒｋｉｎｇ　ｆｏｒ　ａ　ｙｅａｒ　ａｎｄ　ａｐｐｌｙｉｎｇ　again　 ｂｕｔ　ｐａｒｔ　ｏｆ　ｍe　ｔｈｉｎｋｓ　Ｉ＇ｍ　ｎｏｔ　ｒｅａｄｙ　ｆｏｒ　ｍｏｒｅ　ｓｃｈｏｏｌ．

Ｉ　ｌｏｖｅ　ｓｃｉｅｎｃｅ　ｂｕｔ　Ｉ think I'm too lazy to apply myself to the rigors of grad school. I feel like I'm still too young and a PhD is for older people who have aged into themselves a bit more. Also I've been thinking of finding a job in industry rather than pursue more schooling right away. The idea of making some money rather than chasing more schooling just seems smarter to me right now.

My main question is is it alright for me to feel too young for grad school? I feel too young for a PhD although I like learning. I know some of my classmates are in grad school right now and some of my professors finished when they were twenty eight. But I also know others who started grad school in their thirties so I　ｄｏｎ＇ｔ　ｔｈｉｎｋ　Ｉ have to start right away.