So maybe you and a friend are considering getting into Warhammer. I am planning in the future to publish another article regarding their main sci-fi game: Warhammer 40,000. But this article will be focused on the setting of high fantasy.
My experience with these games is vast. I began playing at the age of 10...now being 32, that is over 22 years of modeling, painting, and playing. Age of Sigmar is the most current rendition of Games Workshop's original fantasy game titled Warhammer Fantasy Battles. In the past few years we have watches GW transition from a square based rank and file tabletop game, to more of a free formed skirmish style on circle bases. This has made the game much more accessible for new players.
If you are interested in starting out, my first piece of advice is to just look at the entire model range. Try to find a local hobby shop that sells GW products, as they can help introduce you to the game and also other people who play! Most of these stores will have tables setup with pieces of nice terrain, and often time while shopping you can take a peek over at what could be of your hobby future. There is nothing better than seeing two beautifully crafted armies duke it out on a lucious terrain filled table. I remember my first trip to the local gaming store when I was a young boy. It was incredible, I would just stand there in awe of all the amazing miniatures.
As far as choosing an army goes, I would honestly recommend just picking whatever you think looks the coolest for your first model. Take that thing home, assemble it, paint it. Now your collection, and habit, has begun. Don't be afraid to start doing research online when you are looking to actually play the game. The most recommended purchase would be a start collecting box. These usually come with a big unit, a core group of guys, and for a lot of armies, some sort of leader. If you grab a friend and one of these boxes each, you can definitely start playing pretty quickly. The core rules are also available online on the games workshop website. A starter game with these boxes will take between 1 and 2 hours. It really isn't nearly as intimidating as it may seem.
Another great resource is Warhammer related Facebook groups. There are a few for Age of Sigmar with at least 20,000 members. ANY random question you may have, I am willing to bet that someone their is more than willing to give you an answer or at the very least an opinion. The biggest thing to remember when getting started is that this is a HOBBY. There are times where it will be frustrating, times where you will smile and laugh until you have tears in your eyes. But after 20+ years and thousands of dollars invested, I can tell you it is worth it. This hobby is not for everyone, but with a small enough initial investment... you can find out pretty quickly if it is or is not for you.
If you have always found yourself to be a little artsy, but maybe even not with any artistic skills developed. Just give it a try. I have honestly seen people who could not put paint on the walls of a house to save their life, sit down and paint a beautiful miniature. I have also seen lifetime artists attempt to paint miniatures and have a really rough first go of it. It is always going to be challenging, especially in the beginning. But if you thrive in that sort of environment, then Warhammer might just be the hobby for you. Dwarves, Elves, Dragons, Knights, Demons, Blood Soaked Warriors, Giant Rats.... you name it. Warhammer Age of Sigmar has it all.
The game has mainly driven its focus to close combat oriented units, as well as powerful magic. If shooting stuff is more your thing, look towards the future! (Warhammer 40,000). I personally love the look at feel of the limitless fantasy realms. It has a certain nostalgia to it for me, and for you, I hope you take the leap and feel the same.