Would it be weird to date two siblings? Both of them are fine with it but Idk
My friend, I am but a humble internet advice columnist who goes by a floral pseudonym; I am not the eternal arbiter of what is weird.
If all parties involved are okay with it and no one is weirded out or uncomfortable, and all people are freely consenting, I don’t see any issues.
If you are uncomfortable or weirded out, or for whatever reason you don’t want to do something, don’t do it.
If you’re on the fence because some of you wants something and some of you isn’t sure, that’s okay too! Think it through, talk it through. Identify where your weirded-out-ness is coming from. Identify your needs and boundaries. Think about worst-case and best-case scenario. Practice openness and honesty with yourself and your potential partners.
I am not a practicing Wiccan, but I love their rede, or golden rule: “an it harm none, do what ye will.” Or, if you prefer, “do no harm but take no shit.” Go for what you want as long as no one gets hurt and everyone’s agency is respected in the process.