1) Even as a serious hobby, you should not wait to start your business. Focus on the family photography that you are good at now, make small reasonable investments now to expand your skills and sales ability to get more paid work.
2) Operating a business as your sole income is very stressful and competitive. Talk with your doctors about how this will affect your general health and stay focused on returning to regular work.
3) Work hard on expanding your lighting skills with flashes. You need to maximize the situations where you can work to make money. Buy an external flash, light stand, wireless trigger and practice hard. You can learn to better balance ambient and flash.
4) Investing $1200+ in the 70-200 lens is not a good business move right now. Instead spend a little on business cards, post card portfolio, website, the right licenses and forms to start your business, flash, and backgrounds. Buy that lens only after you have made that much income.
5) Use all the small business advice and counseling help you can find in Norway.
6) You will gain the best advice from actual working photographers in your city. Do your best to talk, network, and assist with them.
7) Be careful about mixing your passion for a hobby and business. Often the best business decisions are not fun or exciting.
Best of luck-