Hi, String – while your picture is a little dark and hard to read, what I think I see is a skirt worn with black stockings.
It is far from being indecent.
What is indecent is when a girl allows herself to be seen showing what is underneath the skirt (whether it is underwear or nothing at all).
I do like the look of your re-enacting garment.
Emmnemms, it is not clear to me why you dislike the idea of wearing a dress, but if you prefer to wear trousers that is your affair, for whatever reason.
Tartan is nonetheless an option for you – you could wear tartan pants, a tartan blouse, a tartan waistcoat (vest) or jacket, or an additional piece of tartan like a scarf, a sash, a plaid, a stole or a shawl.
The possibilities are endless!
Regards,
Mike