Where is your general location?

Trees will grow fine as 'Double Trunk', it's just that if you get wet heavy snow, it will be more likely that the trunks could be splayed or bent outward. Also, the one that gets the most sun may dominate the other and even send out secondary trunks of its own.

At this early age, now is the time to do a trunk reduction. In a few years, it won't look like it had two trunks as the cut one will be absorbed into the main trunk.

If you want a single trunk, you should act this year. I would get a helper to gently pull one trunk to the side, then the other while you stand back and look. This will give you an idea of how it will look short term and which one you should take. Agree with Bill that in a few years you won’t be able to tell. I would do it in winter personally.

I am in SW PA (pgh area). We do get heavy & wet snow occasionally, but it has never impacted the DRs in the front of the house. The hemlocks hold snow but they seem to fair just fine. If we are going to get an ice storm I try to knock heavy snow off of the evergreens.

IME: There's no way to 'fuse' two trunks together. Even if you could, it would look ridiculous.

Removing one of the two trunks is the only way I know of that would accomplish the same overall effect and keep the form of the tree correct.

After all, grafted trees have the side growing the rootstock, cut off after the scion takes and grows to some size, so the principle here would be the same.

Growing the crown in a deliquescent manner might not be textbook but I've seen weirder things. But if that doesn't bother to you, it's your tree and you can do as you like.

Good luck!

:-)

I think I’d take one out. It will fill in pretty quickly. I hear they are very fast growing trees