Maybe get a hat, then you dont need to decide now and could have more options later from longer hair (i dont know any real hair styles and cant really judge). From the picture it seems like you like turtles so you could get a green bowie (i hope i spelled it right) and draw a smile on the front as the head and maybe some legs on the sides

Sorry for not answering your question
you could too try some colors with i think there are chalk colors, they are more expensive but are good for quickly testing it out