It can't be done. You have WAY too few data points. Unfortunately, the corporate world forces many to make such projections and explain under duress any deviation. It's all a little silly.
The best predictor would be from your imagination, based on an examination of the data. Do they show any trend? Any seasonality? What sort of data are they? How were they collected? How were they split into months? Does anything account for months of different lengths? What level of confidence will be sufficient for your audience? What sort of business cycle realtes to these data? Are there any exogenous factors that relate to these data?
There are many questions to ask and answer before proceeding. You must build a decent model.