s = pd.Series([np.nan,2,np.nan])
print (s)
0    NaN
1    2.0
2    NaN
dtype: float64

print (s.first_valid_index())
1

print (s.loc[s.first_valid_index()])
2.0

# If your Series contains ALL NaNs, you'll need to check as follows:

s = pd.Series([np.nan, np.nan, np.nan])
idx = s.first_valid_index()  # Will return None
first_valid_value = s.loc[idx] if idx is not None else None
print(first_valid_value)
None