I would wait a bit. Rosella is a Hibiscus and this plant could be a Hibiscus. Juvenile leaves are often a different shape from mature flowers. I'm not saying it is. But I'd give it a chance. Can you pot it up by itself?

This vendor is selling plants that look similar: http://www.daleysfruit.com.au/Rosella-Hibiscus-spp.htm

Could be the immature nature or the variety. But I'd say pot it up and give it a sunny spot. They are not frost hardy if that is a concern in your location.

FataMorgana

@floral_uk I did separate it yesterday. I put it into a 9-inch pot, I hope that's okay since I can't find info in the internet about Rosella in containers.

@fantamorgana2121 thank you for leading me to the site. One picture actually does look a lot like mine right now. I live in the Philippines so frost is not really an issue here. But it does get cold at times (17C - 23C) esp. during December - March.