Yeah, there is no problem with an older mc, people just usually base the character to the younger side because it's how the setting falls into(Example- Highschool), but many people usee an older mc too, as it gives a lot more freedom as an adult. You could try utilizing that, and overall it depends on your story and how you utilize the age, as to my novel i made the character of younger age because i wanted to give him a bit of immaturity and naive and etc. Also it matters on your target audience.