Doesn't look like the typical tropical Psidium guajava to me. Could be, but usually they are rougher in appearance. What kind of guava did you order? Maybe Strawberry guava (Psidium cattleianum)?

In any case, usually these plants put out more side shoots in the height of the growing season outdoors. In other words -- it will probably fill out in time. Most guavas are large shrubs to small trees.

Here's an old pic of my Psidium guajava -- tropical guava. The leaves have prominent veins underneath.

Hi, it's a psidium littorale.

I'm hoping it gets bushier with a thicker stem.

I'm sure it will.

If it were my strawberry guava I would trim it now to shape it. Mine has to go in the garage in the winter so I have to pay attention to size.