Yes, this is true (don't know about the Dutch but I'll take your word for it). Parthenos can mean virgin, maiden or (very rarely) girl. The normal reading of the word, though, is virgin and the alternative readings all also contain the notion that the female is marriageable which implies virginity (in the culture in which the NT was written). Maiden in English also implies virginity, though modern people rarely seem aware of the fact, which means that parthenos can accurately be translated as maiden. The normal, most natural and, in the context of the NT only valid translation of parthenos into modern English is virgin. In older English maiden would work as in those days the implication of virginity would not have been lost on the reader. Incidentally, I might not know Dutch but I do know German, which seems to have the opposite etymology - Jungfrau literally would translate as young woman but means virgin. Madchen, clearly a cognate with maiden, means girl. In any case, unless the Dutch version omits verse 34 of that chapter (which I very much doubt), it is completely clear from the context that, even without taking into account the subtler implications of the word vis a vis cultural norms, whatever the ambiguity of the translation used, the word parthenos is intended as virgin.
James