icdbd-QA/0015: Does he require to make-up fasting which were missed when he was not so sincere about islam

Fasting became obligatory on me at the age of 14 when I became baaleg. due to ignorance and also lack of proper understanding of deen, I used to fast only 15 days on average on each Ramadaan till the age of 22. After this, I have fasted all along till now Alhamdulillah. Now that Allah has endowed me with proper understanding of Deen, I want to make up for those missed fasts by fasting and offering qaffara. at the age of 26 (presently), how many poor should be fed to make up for those fasts? Also, I want to know, whether the maid servants working in my household and my mother’s household can be considered as poor people? If yes, then can I feed them to count some of my qaffara by inviting them to my house for lunch?if no, then how should i complete my qaffara properly?