Assalamu alaikum warahmatullahi wabarakatu,Alhamdu'lillah ALLAH sub'hanahu wa ta'aala has made me to manage 15 saum a month,generally termed as saum-e-dawoodi (peace be upon him) but as I'm female due to periods they aren't alternate days but are 15 a month,since 3.5years.as i'm 23

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

You did not clarify to us, dear sister, what exactly is your question.

If you are asking about whether or not you will get the promised reward for whoever fasts like the fasting of Prophet Daawood by fasting one day and breaking the fast the other day (i.e. fasted every other day), then the answer is that we hope that you will get the reward mentioned in this regard even if you were not able to match the fasting of Prophet Dawood by fasting every other day. ‘Abdullah ibn ‘Amr used to fast one day and break his fast the other day, but when he grew in age and became weak, he would fast for some days and then would break the fast some other days, and he considered this to be in comformity with what the Prophet used to do when he ordered him to fast the fasting of Prophet Dawood . The Prophet said to him: “Observe the best of fasts, the fast of Daawood: Fasting one day and breaking the fast for one day." ‘Abdullah ibn ‘Amr, may Allah be pleased with him, used to say: “I wish I had accepted the permission of the Prophet as I have become a weak old man.” The narrator said: “And whenever he (Ibn ‘Amr) wanted to gain some strength, he used to give up fasting for some days and count those days so that he would fast a similar number, for he disliked to abandon something which he used to do during the lifetime of the Prophet .” [Al-Bukhari and Muslim]

Ibn Hajar said in Al-Fat-h: “His saying: “And whenever he (Ibn ‘Amr) wanted to gain some strength, he used to give up fasting for some days and count those days …”, it interpreted to mean that the best thing to do is to fast the fasting of Prophet Daawood, by fasting one day and breaking the fast the one day always. What can be deducted from the action of ‘Abdullah ibn ‘Amr is that if someone breaks the fast for some days and then fasts a similar number of days, then this is sufficient and is the same as fasting one day and breaking the fast one day...” [End of quote]

Therefore, dear sister, continue to do the good deeds that you are doing now and Allah will not cause your reward to be lost, Allah willing.

For more benefit, please refer to Fataawa 212923 and 6488.

Allah knows best.