Birkat haGomel is not a berakha that we say for Mitsvot; it is essentially a Birkat haShebah, a form of public expression of gratitude to HaShem.
Every community has its own traditions in the details of this berakha.
Let us see some of them.
MINORS: In many communities boys under 13 or girls under 12 do not recite haGomel. In some communities they do (Halakha Berura p.164 in the name of rabbi O. Yosef z”l, unlike what it says in Yalqut Yosef).
WOMEN: Women also say birkat haGomel, either in the Synagogue from the ‘azrat nashim (=the women’s balcony, Halakha Berura p.166) or in their homes, in the presence of ten men. According to Mishna Berura (Ashkenazi tradition) the husband can say haGomel for his wife. According to Bet Yosef (Sephardic tradition) the recitation of haGomel is not transferable, so a woman has to say haGomel by herself.
TWO TORA SCHOLARS: In principle, this berakha should be said in the presence of ten men from which two of them are Tora Scholars (=scholars that learn Halakhot). But if that is not possible, one can still say haGomel provided there is a Minyan. The tradition is to recite haGomel during or after the Tora reading which obviously requires the presence of ten men.
TIME: The ideal time to recite haGomel is within three days of the event for which one is saying haGomel. The “three days rule” takes precedence over other considerations. Illustration: If a person recovered from illness Sunday and goes to the Synagogue Monday he should say haGomel then, even if he was not called to the Tora, and he knows that he will be called to the Tora Thursday.
EXPIRATION: If haGomel was not recited during the first three days, one can still say haGomel at a later time. The shulhan ‘arukh (219:6) takes a lenient position and says that if one did not say haGomel during the first three days, one can still say it any time he wants (kol zeman sheyrtze). Some rabbis are of the opinion that when not recited on time, haGomel could be said only for the next thirty days. Some say for one year, and some say even after a year. In principle, one should say haGomel as soon as possible, while the memory of the event for which he is thanking HaShem for, is still fresh in his memory (Penine Halakha).
HAGOMEL FOR SOMEBODY ELSE: Although we explained that haGomel is not transferable, as with any other blessing, a person could be included in someone else’s performance, with the condition that the one who says haGomel has him in his mind when he recites the blessing. Illustration, if two, three or more people need to say haGomel, one of them could say haGomel for all of them, if he keeps them in his mind when he recites his berakha. Those who are included should be standing while listening and, in principle, they have to answer “Amen”.
Again, because there are so many traditions in the details of this berakha, in case of any doubt, one should ask his or her own rabbi and follow the local custom.