Time series forecast for small data set
ARIMA could work, I think it's the right approach. It's simple enough to be used on a small dataset, but sufficiently flexible at the same time. If you are using Python, library statsmodels allows you to implement ARIMA regressions. You have to grid search and find the right parameters to find the best fit, and run the prediction.
If you want to know how to do it, take a look here and here.
Alternatively, even simpler models could work correctly, such as a simple moving average (MA), or auto-regression (AR). But that's something you can find from the ARIMA grid search above.