You should think seriously before taking the job and don't do it just for fun.

在接受这份工作之前你应该认真考虑，不要只是为了好玩才做。

youdao

I didn't do all that work just for the fun of it.

我做这一切并不仅仅是为了好玩。

《牛津词典》

But it's not a race, it's really just for fun and the best thing would be to take it easy the first few times you do it and then see if you can gradually improve your time.

但这不是一场比赛，真的只是为了好玩，最好是在刚开始的几次比赛中放松一些，然后看看你是否能在时间上逐渐提升。

youdao