Swimming or Guitar

I thought of looking at musician's friend website for some good deals on guitar.  I really want my son to get involve with something rather than be scared of doing anything  just because he is scared of  possible failure.  His sister is doing really well with extra curricular activities tat he is worried, he won't be as good as her.  I told him that it doesn't matter, what matter is that he try.  I notice that he is  fearless in water so I told my husband that we should enrol him in swimming lessons.