[name]Adelaide[/name] was our first choice for a girls name and we did end up using it for our first daughter.
It fit all our criteria: we liked how it sounded, we liked its meaning, we agreed on it, it sounded fresh without being too strange and it wasn’t very popular.
Lots of people seem to like it on this site, but so far, I haven’t met another [name]Adelaide[/name] in our area yet (but I’ve met a few babies named [name]Holden[/name], [name]Eli[/name]/[name]Elijah[/name], [name]Asia[/name], etc., so there are names being used a lot, though [name]Adelaide[/name] still doesn’t seem like one of the popular ones). We live in [name]Canada[/name]. My husband, who travels around a bit for work, has met 2 other Adelaides, one was close in age to our daughter, but the other one was a few years older. I have also come across a few other school-aged girls with the name in a few magazines.
I don’t think it is going to be the next [name]Sydney[/name] or [name]Madison[/name] (at least I really hope not) or even [name]Madeleine[/name] (another name we liked, but seemed much more popular than [name]Adelaide[/name]).
I say go for it, especially if it satisfies all your criteria and you both love it. Maybe it will explode in popularity, maybe it won’t. There isn’t any way to know for sure (if you are really concerned about it, you could compare it’s position on the social security names listings from the last few years).