Cultural appropriation or no?

I personally feel like there are two elements to really watch out for in situations like this. The first is taking something from another culture and trivializing it (ie, turning something full of tradition into a mere fashion accessory, taking something associated with a history of oppression and treating it like a fashion decision, etc). The second is when the original culture is excluded from the tradition, article of clothing, etc. This includes considerations like who makes something and who benefits from your purchase/embracing of an item associated with another culture. It's particularly problematic when the people who benefits from the popularization of a cultural item is NOT a person from the culture associated with the item.

I don't know enough about headpieces to weigh in on whether this would violate consideration #1. But my suggestion would be to also look into who you'd be buying a headpiece like this from and take that into consideration when making a decision.

I'm going to give you a perspective here, but I'm also marrying an Indian man so the rules are slightly different.

I'm having an Indian ceremony AND an American ceremony. Me, my family, and my friends will be donning traditional Indian attire. I would be getting henna (mehndi) too if I wasn't going to be in a white lace dress the next day too. My future family was thrilled to find out my family and friends wanted to wear Indian attire. It's not seen as disrespectful when you're not making a costume out of it, like on Halloween.

However, I will also ask my FH what he thinks about this. If you're super worried about cultural appropriation, I'd just go with a flower crown or the second headpiece because it's more European.

Here's some more information I found on this:

The maang tikka is a typically Indian hair adornment, placed on the bride’s hairline with a drop pendant that gracefully sits on her forehead. Traditionally, an Indian woman wore a maang tikka for the first time on her wedding day. It is an essential element of the solah shringaar, or the sixteen traditional bridal adornments. It is said that the pendant of the maang tikka sits on the agya chakra; a spot on the woman’s forehead which is the seat of preservation. It signifies the holy union of male and female, on a spiritual, physical and emotional level.

I'll be wearing one, but it's not a full headpiece, just a jewel that I bobby pin into my hair.

Yes, this too. I'd say if you do go for it, make sure you are buying it from an Indian seller!

What about this, is this okay to wear to prom?