Sure, go ahead and plant it. It is pretty common to find seeds already sprouting in ripe fruit.

Once you grow it out for a year or so, you could graft known varieties to it. Otherwise you may end up waiting many,many years for fruit and may not like it when you get fruit. I think Mango seedlings can be quite unlike their parents.

Here is a very good site with a video that shows how to graft Mangos.

Or you could save yourself a few years time and order a grafted "Condo" mango variety from Pine Island.(G) Then you could grow it in a container and move it inside during cold weather.

Lisa

Here is a link that might be useful: Veneer grafting video

Leona, on the "Fruiting Mango" thread here, there is a lovely photo of a Carrie Mango with fruit on it-with the Pine Island tag still on it(G). A really nice tree, and typical of what they sell.

I am not affiliated with PI in any way, other than as a happy customer.

Lisa