I think that you should think about what feels right to you.
One daughter did take one semester abroad when she was in high school. The following semester we hosted the daughter of the family that she had been staying with. This was a very positive experience for all of us. This particular daughter ended up being 5 for 5 in university acceptances so it at least did not harm her applications.
One issue is that if you take a semester abroad during your senior year, then you are going to want to have all of your university applications in before you go abroad.