What is the ruling regarding my fasting, which I used to delay until sunrise due to my ignorance of the time of imsak (the start of the fasting period), and does the ruling differ based on my age of puberty at that time?

The questioner is not obligated to make up for fasts she missed before puberty, or fasts about which she is unsure whether they occurred before or after puberty. However, for fasts missed after puberty, she must make up for the days on which she consumed fast-breaking things after dawn, even if she was ignorant (of the rule). She must strive and investigate to determine their number. Her ignorance of the start time of fasting is not an excuse for not making up the fast, unless she is a new convert to Islam or grew up in an ignorant environment far from scholars. Expiation (kaffarah) is not required.