The more unique a bit of knowledge is, plus the more interesting it was at the time, multiplied by how frequently you have thought about it since, is basically the formula for the strength of a memory. So a relatively uninteresting thing, you have done some minor variation of hundreds of times and haven't really thought about since, is gonna take alot of effort to willfully recall. You would need some sorf of trigger to easily recall it, as triggering a memory is a much more powerful way to recall it.
You are normal, as you get older, even just early adulthood, more and more of your life will feel that way in hindsight. You don't do as many super memorable things as you used to, and you just have more and more stuff packed into your brain. Makes it harder for individual memories to compete, more and more of them will just fade out as unimportant things you don't prioritise remembering, or even recording in the first place.
You probably have heard people older than you remark that life goes by faster and faster as we get older, this is mostly the cause of that feeling. Obviously, time is moving the same speed, you are just making fewer important memories worth recalling.
If you went to a concert this week, you would probably have an easier time remembering what day it was, or what the drive to and from it was like. But if the whole week was TV shows, videogames and meals primarily designed to be thrown together for sustenance, none of it will be super memorable.
You can technically put effort into remembering even mundane stuff, just focus on it more as you are doing it, and repeatedly practice recalling it as you go. It might be a fun exercise for a week just to prove you can do it if you want to. But it would be alot of effort to keep up for longer. If you are otherwise happy with how things are going, no real need to change though. And if you do want things to be more memorable, find ways to do more unique things that you have an interest in and that are worth spending time thinking about afterward too.
Edit: me personally, As with most people in this thread, I have a very good long term memory, but a very bad working memory, and almost no willful recall, I generally leave visible reminders or set alarms for stuff I need to remember "tomorrow". If someone asks me to do something, and I don't do it within 15 seconds, I won't recall that I was asked unless something triggers the memory. So I generally do stuff right away, but I am also easily distracted. And I don't always remember that I need to warn people to re-ask me if it has been a minute or so and I didn't do it, but I have slowly gotten better as it works into my rote/routine memory to sequentially trigger that response based on the incoming cue. Needs to be more consistent to become rote.
And yeah, Autism for sure, ADHD probable but haven't checked.