About a year.
I advice you to not buy anything unless you feel limited by not owning it. There are stuff I'd like now, but I don't think I need it. Learn the basics. I've read that most people go for a tele zoom as their second lens. I went with a wide angle zoom, because that was what I felt I never was as wide as I wanted with the 50mm prime I started out with. When you know what you want, and really itch by not having it, then it you can buy it.
If I were your guru, sitting on a mountain top and drinking tea with a long, thin mustache, I'd order you to go out and learn composition, understand your camera, only use your eyes by looking through the viewfinder - you should learn to compose shots without having to look through the viewfinder. Know your camera, know how to handle it smoothly. Set the ISO without having to search for the button.
Start with foundation. Then build walls. The roof comes next. Then comes the chimney.