Thank you, Sean,

So that's the current version:

338. Kacci abhi.nhasa.mvaasaa'ti raahulasutta.m. Kaa uppatti? Bhagavaa
sammaasambodhi.m abhisambujjhitvaa bodhima.n.dato anupubbena
kapilavatthu.m gantvaa tattha raahulakumaarena "daayajja.m me sama.na
dehii"ti daayajja.m yaacito saariputtatthera.m aa.naapesi-
"raahulakumaara.m pabbaajehii"ti. Ta.m sabba.m
khandhaka.t.thakathaaya.m (mahaava. a.t.tha. 105) vuttanayeneva
gahetabba.m. Eva.m pabbajita.m pana raahulakumaara.m vu.d.dhippatta.m
saariputtattherova upasampaadesi, mahaamoggallaanatthero assa
kammavaacaacariyo ahosi.

'I wonder whether because of continuous living together' - says Rahula
sutta. What was the origin [of this sutta]? The Blessed One, having
awakened to the highest wisdom, from ground under the Bodhi tree went
in due course of time to Kapilavatthu. There when prince Rahula (*
Ro: Vin. 1.82) asked for going forth by way of inheritance:
'Contemplative, give me going forth by way of inheritance', he
commanded Saariputta Thera: 'Give going forth to prince Rahula'. All
what is said about this in Khandhaka-A.t.thakathaa
(Mahavagga-A.t.thakathaa, paragraph 105, Ro: 5.1004) should be
grasped. Now having went forth in this way, when the prince Raahula
had attained the proper age (* 20 years) the elder Saariputta also gave him the
full admission, and his teacher in the proper ways of doing the formal
acts of the Sangha was Mahamoggalana Thera.

Please tell, where it is written that his original going forth was at
the age of 7 years?

338. ... Ta.m bhagavaa "aya.m kumaaro jaati-aadisampanno, so
jaatigottakulava.n.napokkharataadiini nissaaya maana.m vaa mada.m vaa
maa akaasii"ti daharakaalato pabhuti yaava na ariyabhuumi.m paapu.ni,
taava ovadanto abhi.nha.m ima.m suttamabhaasi.

This sutta told that the Blessed One continuosly exhorted him since
the young age, as long as he did not attain the Noble state of
existence: "Endowed with a birth as a prince, let him not
have arrogance or conceit on account of his birth, lineage, clan, and
beauty of complexion."

va.n.napokkharataa = beauty of complexion, 'being like a lotus'
nissaaya = on account of
aadini = closing a quotation, 'this and such like'

Metta,
Dimitry