question regarding reality shifting

so let's say I want to shift back in the past for example on 8th of September 2006, 20 years ago that is, to that reality I mean where is 2006, would I have the memories from both realities? for example my current memories on my current reality since I was baby and the mamories I had on 8-9-2006, my desired reality? for exmple what I ate the previous day 7-9-2006 or what extracurricular activities I had for example that day? if I had guitar lesson or English for example or basketball, you get the idea, it is very important for me to remember that's why I am asking thisin case you are wondering, thanks so much!!!