threw in her two cents

Reader's Digest 5月号の記事 'LIFE in these United States' からの引用です。
A few of us were discussing the perils of drinking and driving when my five-year-old granddaughter threw in her two cents.
"I can see why it would be dangerours to drink and drive," she said. "The straw could go up your nose."
"threw in her two cents" の後で、5歳の孫娘は子供らしいコメントを挟んだのですが、"threw in her two cents" はその様な意味になる慣用句なのでしょうか？　辞書を見ます。
辞書に "throw in two cents" の項目は見当たりませんでしたが、 "put in two cents" での説明が次の辞書にありました。
・Merriam-Webster's Online Dictionary: to express one's opinion: You will each have a chance to put in your two cents.
同辞書には "two cents" の項もあり、次の解説がありました。

or two cents' worth: an opinion offered on a topic under discussion: send your two cents' worth to your senator
Usage notes: The US-originated terms Two cents and two cents' worth have gained some currency in the UK at the expense of the native two pennies' worth even though the cent is not a unit of currency there.
two cents, two cents' worth (of US origin)
two penn’orth, twopenn’orth, two pennorth; tuppence worth, tuppenceworth; tuppenny's worth (all UK)
Wikipediaには "My two cents" の項目があり、ニュアンスも含めた次の詳しい説明がありました。
"My two cents" ("my 2¢") and its longer version "put my two cents in" is an American idiomatic expression, taken from the original English idiom "to put in my two-penny worth" or "my two cents". It is used to preface a tentative statement of one’s opinion. By deprecating the opinion to follow—suggesting its value is only two cents, a very small amount—the user of the phrase, showing politeness and humility, hopes to lessen the impact of a possibly contentious statement. However, it is also sometimes used ironically when expressing a strongly held opinion. The phrase is also sometimes used out of habit to preface uncontentious opinions. For example: "If I may put my two cents in, that hat doesn't do you any favors." (A polite way of saying, for example: That hat is ugly). Another example would be: "My two cents is that you should sell your stock now."