Economic Regression (Model) Economic diversity

Hey guys I need help. I am currently analyzing the difference between GDP growth of small island economies. I argue that these differences are due to the composition of the economy. The more diverse the economy is, the higher its GDP growth. Diversity refers to the income from the different sectors of the economy (primary, industry, services).
Hereby, I have to devise an economic model where:
economic growth (annual GDP growth) = B1 +B2+ … + error
Does anyone know if this is acceptable in the econometrics? And should it be a stochastic or non-stochastic model? And which independent variable should I include? And control variables?
One more thing, N = 2. For a dataset/period from 2001 to 2017. Is this allowed?