It is up to you if you want to wait or use it this year; but I would consider it science.
We did Apologia Astronomy last year, my oldest was in 2nd grade (7 turning 8 late in the year) and child #2 was 5 turing 6 and in Kindergarten. I didn’t expect child #2 to get much out of it, he just listened in here and there, but he ended up loving it, and rarely missed out. Both of the kids really liked it and I can’t believe what they remembered. I think it just depends child to child.
We did Outdoor Secrets for the previous year and really enjoyed it as well.