Princely Prefix by a Program in Pattern
Pip, score = 38
eyli:
&quot;Once
when0
I was
si01x
year5
old I
0sMw1
1M 0&quot;
X1RMh
Rnsxy
iR:'M
'aiR 
:5'si

Alphabet:  &quot;'015:IMORXacdehilnorswxy
(I sure would hate to try this in a real programming language.)
Explanation:
eyl      Statements consisting of single variables are no-ops
i:       Assign to i the following:
&quot;Once
when0
I was
si01x
year5
old I
0sMw1
1M 0&quot;    ...this string
X1       ...repeated once (no-op to get alignment right)
RMh      ...with all 1s and 0s removed (h is preinitialized to 100)
Rns      ...and all newlines replaced with spaces.
xy       More no-ops
iR:'M'a  Replace every M with a, assigning result back to i
iR:5's   Replace every 5 with s, assigning result back to i
i        Auto-print i