I just started running this year and a marathon in a few years is also my goal. It might take me a while to build up to it. The main thing is to be consistent. Start now and try to slowly build up what they call a base. Beginning with a 5k and working your way up is great advice, and I would also add that it would help to start reading as much as you can about the subject so that you can learn how to go slow, listen to your body and eventually run a marathon injury-free. If there are any beginners running clubs in your area that can be a great way to get awesome advice and support as well.
I have no doubt that if you start now and train smart that you can do it
