Chinese: whath does it mean?

“现在的努力是为了小时候吹过的牛B” is partly an intentional erratic writing of “现在的努力是为了小时候吹过的牛皮”
The Pinyin of 皮 is slightly similar with the pronunciation of B.
Pinyin: xian zai de nu li shi wei le xiao shi hou chui guo de niu pi.
It is meant that to be diligent now is to fulfill the big talking(bragging) wish made while young.
Here in Taiwan, 吹牛 is much more commonly used than 吹牛皮。In the phrase of “吹过的牛皮”, in my opinion, “过” is redundant.