I believe Christians cannot look the way they want,
but the way God wants them to.
I will mention Bible verses to prove this.
How a male Christian must look like:
a full beard,
no bald head,
do not shorten the sides of the hair on the head or beard,
no long hair,
no tattoos,
only decent clothes,
men's clothing only.
How a female Christian must look like:
no beard,
no bald head,
long hair,
no tattoos,
only decent clothes,
women's clothing only,
she must cover herself, that means,
no tight clothing,
and no nudity.
Sources: Leviticus 19:27, 21:25; 1Corinthians 11:14-15,
Of course, there can be natural exceptions,
for example, someone cannot have a beard or hair on their head.
Such a person is excused.