I agree with the other poster that Junipers are outdoor trees and will
die inside. I've heard of people doing complicated things with
refrigerating them during the winter, but I don't think it's worth it,
get an indoor tree.

There are a number of trees you can keep indoors. Ficus is probably
the most popular, and I've got a couple. I've heard you can keep
chinese elm, bouganvillea, texas ebony, olive, and fukien tea inside.
I'm sure there are others.