First of all, be very sure that this is you want because once you start on hormones etc, there is no going back.
In the meantime, you will find a lot of very useful information here in the forums regarding make up tips, passing in public, altering your voice etc but although you want all this by tomorrow, it just doesn't work that fast. It takes a while to firgure out what works for you in terms of make up for example. We are all different and what works for one may be unsuitable for another. Take it easy and enjoy it. If you have your mother's support, she will able to help you as well. Transitioning is a slow process to get it right, it doesn't happen overnight. It takes months, even a year or two. There is a lot to learn in becoming a woman, it isn't just about putting on a dress and some make up. There are a lot of changes that you will have to undertake.
Then there is transitioning in the workplace. For many, a scary prospect. Transitioning is very public. You can't go from 'Dave' to 'Jill' witout people noticing.
Don't feel I am trying to put you off, I'm not. But it isn't always easy. That said, you have youth on your side and so the sooner you can transition the better. However, do it properly and, as far as hormones are concerned, under medical supervision.
To that end, have you told your GP yet? If not, and you are sure this is what you want, then do so as soon as possible in order to start the ball rolling in getting the necessary referral you will require in order to begin your transition.
Anyway, you asked about shaving and your voice. You can work on your voice straight away and youtube has some good videos from women who have acheived excellent results. Don't be dissapointed if you can't match them, even GG women have all types of different voices. You just need a voice that you can use in public and not be read.
Shaving - a wet razor is best and shaving against the grain will achieve better results as it is a closer shave. ultimately though, you will very likely need to consider laser hair removal and electrolysis, neither is cheap but they effective and for most women, very necessary. It isn't just your face remember, it's your chest, back, legs etc etc. You can buy an epilator for home use which will remove hair quite effectively but it can be very painful and they will grow back.
The road to transition is long and can be rough in places but ultimately, it's a great journey.