I converted (reverted) to islam when I was 30 by myself no witnesses alone. I do not know if I converted properly for one this always makes me question is it valid and also how many prayers and fasts should I make up for now am 42 have prayed many and fasted many but I feel I should just make up for last 12 years to have a topped account of my obligations and do I include the mentsral days as well ? Do I make up since 12/13 years old to make sure I have no debts in those and leave upon my death on others for these when I can do my best to do these myself as these are my responsibilities. Or since I converted to Islam at age 30 so do I make up from 30 or since first menstral? Also for missed prayers to do is the qunoot wajib to do it or mustahab since I have many many to make up for? Please tell me so I can work on these things and if I am not been able to complete by my time to go can any charities feeding homeless or anything can help on these to help me ? Please help answer these

Please let me know how u converted

You don’t need witnesses, just to state the shahadah