For anyone else that might be considering Rosetta Stone - try checking your local library to see if they have it as a resource. They are partnered(?) (or something) with EBSCO, I have access to 23 languages through the library. It’s unclear if you get the full course, but if you just want to try it out it is somewhere to start.
You definitely need a child brain for true immersive learning.
It can help a lot to do a lot of things in the target language from the get-go, if only because it can put students at ease about operating in the target language, but adults need lessons and drills for grammar and vocab – period.
Bonus language learning the cheap way: Found a Spanish language National Geographic in a little free library near me. Score! Free reading material, and it’s very different from the book I’m currently reading, which is a children’s chapter book. (Honestly, I think NatGeo will be easier – a lot of fancy Latinate vocab shared with English, compared to the kids’ book where the English counterparts are Germanic, and there’s a lot of Arabic vocab in the Spanish.)
I wonder about doing the immersive exercises after a certain level of structured learning? Past a certain point duo just bores me