It’s totally valid in most cases. It’s technically only supposed to be used for a question, but language is based on how it’s most commonly used, with those “rules” only applying in extremely formal situations. With the prevalence of informal text-based communication, many people use it to indicate being unsure, like how you used it. I just wanted to continue the chain of grammar corrections (which is why I used the wrong “its”/“it’s” at one point). Also, you were right about the quotes.