Wardell, you tend to post a lot of questions that you expect to have black/white yes/no definitive answers: in most cases you've already made up your mind what you believe anyway, and sorta/kinda dispute the answers you get.
You are going thru a difficult period right now, with many hurdles seeming to block your way toward the life you want. Only very recently did you reveal the full extent of what you're dealing with: since we had no way of knowing until you told us, the answers you've received previously could not possibly account for your specific situation. So while you may have thought we were being obtuse or not "getting" you, it was only because you hadn't fully explained all the things you have to cope with. Now we know (at least those of us who saw your recent biographic post).
Putting that aside, this "memory" question involves aspects of both philosophy and biology. There is no definite answer to such inquiries, only evidence that provokes a subjective response or belief. The idea that our memories can become faulty, unreliable, inaccurate, etc is a nuanced topic. In the literal sense, yes: your specific memories about your cousin (for example) are not likely to change. It isn't the memories per se but the emotional attitude we have toward them that can give them undue power for good or ill effect on our lives. Topdog expressed this perfectly (and poetically) in his post above.
There is a school of thought that all time is actually simultaneous, past-present-future occurring as a three-dimensional interactive sphere of energy. Our human form can only interpret this as a linear progression, but our minds unconsciously access the true time source in a manner we don't fully comprehend. This ties in with the "memory is not static but a living changing process" theories now being studied.
Perhaps you've heard of the scientific notion that anything we observe or study will throw off some degree of inaccurate information, because the very act of observing and studying something (molecules, frogs, solar flares) alters the momentary nature of that thing. This is what that memory study you cited is trying to get at: memories are not exempt from this phenomenon. Each time we recall a memory (or conjecture the future) we are focusing the energy of our attention into it: cyclically, that energy ac
ulates to where we make use of it in positive or negative, conscious or unconscious ways.
You're fairly young compared to some of us who respond to your posts, so its perfectly fine if you view such vague philosophy as annoying bullshit. Most people do: like you, they have more important day-to-day issues to think about. As you get older, and some of your immediate burdens lessen, you may be more inclined to consider such ideas as valid or interesting. Or maybe not: it doesn't matter unless you personally think it does.
The only indisputable point in the whole mess is that a positive attitude will eventually lead to better results than a negative attitude, whether in relation to memories or anything else. While we can't literally change the past or the future with only our thoughts, those thoughts can have a powerful enhancing or destructive effect on our lives moment to moment. It is jarring indeed when you fully realize those moments add up to years and decades faster and faster.