Welcome to the forum!
I'm a new modeler, only completed two kits, and I handbrush. Handbrushing is fine, it just takes longer to complete a figure.
For a first kit I would look for something without too many small details, unless you have really steady hands. Also it's a good idea not to buy a kit that you absolutely love since the first one is going to be such a learning experience and you're probably not going to be too happy with the results. Some people never even finish their first. Picking a kit without too many different colors is also a good idea since mixing colors is a pain.
I would look through this section of the forum for other tips. For instance, for the shading I would recommend using pastels rather than washes. It was such a nightmare for me trying to use a wash correctly, which means diluting the paint until it runs in the crevices. I have only used a black and brown pastel, so a great expenditure of money is not required.
For brushes I would get some flats in a few different sizes, 2 & 4 maybe, then some detail brushes for the eyes and such. I have as small as a 25/0 brush. You could also take a larger brush and cut hairs away until it's the size you want.
Masking is using masking tape to prevent paint from applying to certain areas. It's just like masking off a room when you paint it. Masking shouldn't be necessary for handbrushing since you will have control when painting where two colors meet. If an accident happens and you get the wrong color of paint somewhere, you could paint over with the original color or I sometimes scrape it away with my x-acto knife, but that's just me.
Anyway, good luck and just have fun!