I don't understand the "downvotes" either. le is used before feminine nouns, even when the initial segment is a vowel. One encounters l', e.g. l'erbe, but that is now archaic.
ma con piena letizia l'ore prime, cantando, ricevieno intra le foglie che tenevan bordone a le sue rime, Dante Purgatorio 28
From a phonetic point of view, I can say that it's a phenomenon you should expect after a nasal sound like "n" (or "m"). The "u" that comes after simply "opens" a little —in phonetic terms, which means that the mouth makes a more open movement than it would in other circunstances—. She is not really saying "una", she's simply pronouncing a longer and more open "u" because the preceding "n" sort of forces the mouth that way. It's the same thing in spanish. Try it yourself and you'll see what I mean. :-)
steveschwaby--if you learned a new phrase or idiomatic expression then i suggest the comment isn't silly. Aside from that observation, I and other users have often noted that humorous comments by users is one of the attractions of the site which keeps users coming back and gettin' after learning italiano.
English advice: in informal speech, 'How do I...?' can be used to mean "How would I...?" or "How can I...?".
"How am I...?" would be more like "Why do you say that I'm becoming a man?" or "What do you notice that makes you say that I'm becoming a man?".
However, since Italian uses the present tense where English usually uses the present progressive tense, I don't know why "How am I...?" would be incorrect.
If it is incorrect, then I don't know how an Italian would express "How am I...?". Maybe they would use the present progressive tense (in Italian), or maybe they would just say "Why do you say...?".
Thanks for your extensive reply, mskycc3. Perhaps also, as elsewhere, it might depend on the context. I know that translation is not an exact art/science (thank goodness) so there's always room for different nuances of meaning - & for me, discovering these is part of the beauty of languages! Thanks again...