Fertilizing/ care questions for a chocolate drop volcano queen

[lady_bug22]

I bought my first orchid today and it is a chocolate drop volcano queen- obviously not in bloom (she will in the fall tho) but she is very small and I'm thinking of repotting her soon because the roots look like they coming through the medium (is that the correct name for it?). Is this right or should the roots totally be through the medium before I repot?

While I was pondering that, I realized I had no idea what fertilizing routine or times I should fertilize her. I have bought phosphorous rich but also containing Nitrogen and it's specificaly for orchids. The brand name is Better Gro: Orchid Bloom Blooster... so it has no urea and I water her with distilled water I get with a rain catcher or spring water since it has no trace amounts of minerals in it. The sites I've seen said to water her when the medium is completly dry, and it's vrey important not to over water because blooms may appear yellow and weak.

I live in the south so temp, light and humidity aren't a concern here and i'm a semi- experienced gardener of other things, but I always dreamed of growing orchids since I was a child. I want do this right, and thanks to all who respond.