Halanna

Yes you should live like it's fine.

Don't cut your hair or do anything to your body to please someone else, or worse, strangers.

Now, there are different degrees of "how it looks". Aside from the obvious, your hair always needs to be clean, at a minimum brush/comb it to the preferred way you wear it. I'm not sure what you mean by "messy". Some people spend a lot of time to style their hair to look like they just rolled out of bed.

There is no right or wrong. If you look in the mirror and are satisfied with what you see and your current style makes you happy, then leave it alone. You will never be happy making those type of changes for the sole reason of making others happy.

Embrace who you are, there is only one you.