I think it is a blessing in disguise. Planting fruit trees that are not grafted is a large loss of time, money, and valuable real estate. You will be waiting for fruit that will never come. There are some types of fruit that will produce from seed but mango does require grafting. You may get some fruit but it will be different than the fruit you ate. And likely not tasty. Go buy a proven hybrid. There are many.

MANGONEWBIE - I would move it out into a semi-sun/partly shaded position for a few weeks and then introduce more sun over time. But just remember. Full, naked all-day Sun on any potted plant will cook and dry out the roots and make the plant suffer, and Virginia does get some toasty summer days. The change in light will probably stimulate more growth, and so, yes, I think you can leave it outside for the whole summer up until the first frost warnings. But just keep an eye on the moisture level of the soil and don't let it dry out too much between waterings.... And...they don't need a full 12-14 hour sun to do well and fruit, so that is the good news..... good luck - MangoWoofie

Depends on what climate you're in as to how damaging it might have been. You could carefully cut it open to see if the seed is turning black or if roots/shoots are developing.

daleyc, the only benefit to soaking those seeds large enough to conveniently soak then handle - is soaking can allow moisture not nutrients to penetrate to seed coat and begin the germination process. But again, in those seeds that are large enough to handle which have less penetrable seed coats ;0) No need for any fertilizer before any seedling has true leaves - it's already there and present. Within the seed coat is the embryo and nutritional materials used to sustain the germinated seedling until it is able to make its own food via photosynthesis. You might start with a very diluted fertilizer after a set of true leaves have appeared, nothing to gain by rushing it - or doing it before germination takes place.