Sort pyplot figure x axis values from oldest to newest

Bosten_all["OCCURRED_ON_DATE"] = pd.to_datetime(Bosten_all["OCCURRED_ON_DATE"])
color =, 5, 100))
Bosten_all["month"].value_counts().head(20) = color, figsize = (15, 9))
plt.title('Distribution of crime by each month in Bosten ', fontsize = 20)

i have this figure but want to make the order from oldest to newest. currently it is ordered by size from biggest to smallest