Where do you live? Without knowing that there's no way to help.

I live in a humid subtropical climate. It gets between 100 degrees in the summer, and 20 in winter.

That's too vague and not going to help now as I still can't tell what your weather's like right now - what hemisphere and country are you in, near what large well known place? And what's available in the way of protection, e.g. do you have an unheated porch or shed; what about a cool basement? The point is that your tree's used to being indoors, and without being acclimated slowly to outside, could possibly be shocked by the change... but not necessarily, depending on the above. I should also tell you that it's late to be inducing dormancy - plants are already making plans for growing again, even if it's too cold to show buds yet.

I live in the northern hemisphere in the U.S next to New Orleans, Louisiana.
I have an unheated shed in my backyard that is available.

Thank you! Your tree should absolutely be outdoors every minute of its life and if the pot's very small, then sink it into a larger one of mulch in a place in the sun, but out of the rain til all chance of frost has passed. Don't water if the soil freezes hard, otherwise do allow enough of it to dry so the soil isn't soggy all the time. All that being said, it's as likely your tree is already in a bad way as roadside vendors are notorious about selling anyone cuttings stuck in pots (not yet anywhere close to being trees) in water holding peaty muck that can't dry or drain properly (should be mostly grit with some bark in there) and pebbles glued to the soil. They pretend to be knowledgable but give terrible advice on how to water, etc., and end up discouraging people from learning bonsai properly, as their trees don't make it without proper care. N.O's weather will never be cold enough for you to worry about wintering anything, certainly not a juniper, but I strongly suggest you find a local club to join and do a lot of reading before spending again.

Thank u so much!! Your advice is very helpful. I have one more question though.
When I got the tree, it had a bunch of small rocks on the top. I had read that having these on there was bad for the tree, so i took them off. Later on I noticed that the tree was very insecure and that it wobbled when i picked it up. So I took some regular potting soil and put a layer on top. It seems more secure now, but I don't know if that soil is okay for the tree. I am thinking about repotting in some better soil all-together. Any advice? Thanks.

-Jonathan

Yes, as I said you'll need a better mix, one that's at least 50% grit - maybe 1/3 of that being perlite and the rest small aquarium gravel (the glassy-not-enamel kind), though there are many types of grit around. The soil should be coarse - not tiny fibres like peat that will compact, so you get immediate drainage. Once you've done that (wait til March) then you can water more often without fear of rotting roots. By then, hopefully, you'll have learned about root pruning and how to wire the tree into the pot properly so it can take breezes, etc.

Okay. Thank you for all of your help. I really appreciate it!

-Jonathan