im new to taking care of bonsai's and I would like to know what kind of bonsai I have.
Looks like a ficus retusa to me. Please tell us a bit about how long you have had it as well as the environment it lives in, Your watering practices, etc, etc.
If those rocks are glued on, Please remove them they are only inhibiting aeration of your soil as well as making it impossible to determine if it needs water. A picture of your soil would be helpful to see if it is decent.
Stop by the stickys at the top of the forum for some care info & See the following links for more tips: https://www.bonsai4me.com/SpeciesGuide/Ficus.html & https://www.bonsaihunk.us/ficusforum/FicusForum.html
Also some general bonsai care tips here; https://www.bonsai4me.com/Basics.html
I have pictures.. but im not sure how to post them on the forum.
We can see them - See here for more tips: https://www.helpfulgardener.com/forum/viewtopic.php?t=3557
I was curious to to see if there is a way to tell how old it is.
There is an extremely accurate way to tell... BUT - You won't like it.... [You have to cut it down to tell - Don't do that
The age of a bonsai is not really relevant anyway as it is all
about the illusion of age
some of the leaves are brown and bumpy..
I was reading on the internet that there is indoor and outdoor bonsais and I wasnt sure if mine was an outdoors kind.
Ficus are tropical and therefore do not appreciate Jersey winters - They prefer life outside during the warmer months though as you will discover in your reading of the links provided.
One more thing, You should know that an office is not an appropriate environment for long term bonsai health [& ultimately survival] Lighting and humidity tend to be inadequate and often the heating/AC plays havoc as well.