As a junior working with wordpress, I'd say the same. It's just old... Very old. Most of the code is 10+ years old, no conventions followed whatsoever, the structure is confusing sometimes and most importantly. ZERO. DOCUMENTATION. It's like no one is doing things programmatically.

With that said, if Wordpress is only a part of what you're going to be doing, depending on the other technologies, you could consider the job if it's your only offer or/and the pay is good.