You will need as many people as it takes to create and sell your first game.
How many and what kind of people these are depends solely on the game you want to make and how ambitioned you want it to be in regards to gameplay, graphics, sound, writing, world-size etc. Depending on these factors (and many more), the required project team can be anywhere between one and one hundred people.
To get an estimation for how many people you need, you need to do the same thing which needs to be done for any software development project: Create a project plan. Clearly define the scope of your project. Create a detailed list of all the things which need to be done to complete the project. The more detailed the better. "Make graphics" is much too rough. "Make tilesets, player sprites and monster sprites" is better, but still not nearly detailed enough. "Make about 20 different monsters, sized 32x64 px, each with 12 different animations consisting of 1-6 animation phases each" starts getting you somewhere.
Then make an estimate how many man-hours you will need to complete each of these bullet-points. Then double or triple that estimate, because experience tells us that the effort which goes into a software development project is always grossly underestimated, never overestimated. In some cases you might not have a good idea how long something will take, especially when it is something you never did yourself. In that case, do your research and find out.
You should now have a rough idea what human resources you need to create the game. The next thing you should ask yourself is if you can afford these people. Anyone with a minimum level of professionalism will not work for free, and you will need to pay these people even when it turns out your game doesn't sell a single copy. This worst-case scenario is something you always have to plan for. Total project failure is a possible outcome of every software project, even those managed by the most professional project leaders. When you can not afford to lose every single cent you invested in your project, then do not take that risk.
This might be the moment where you realize you are trying to bite more than you can chew and might decide to downscale your project to something you can complete on your own without external help. In that case all you have to lose is the time you invest. Or maybe you do have some savings lying around and are willing to bet that money on your project?
Whatever decision you make, I honestly wish you the best luck.