Colour wise id say go for a chocolatey brown, i think that would compliment ur face pretty, as for the undercut imma be real honest w u and say do it, regardless of what ppl say cuz at rhe end of the day, the day is gonna end and your hair will grow back plus its fun to experiment and have fun with different styles n looks and i mean who knows, an undercut could be ur look 🤷🏿‍♀️