This will not affect your original timeline.
And lets take take this hypothetical a step further:
Sceanrio 2:
Say, in the alt-timeline, present-you arrive in the year when past alt-you were 10 years old, your original parents/guardians/caretakers dies for some reason on this timeline, would you care enough about your alternate-self help them? Like take on the role of a parent/guardian in place of their now-dead parents? (Basically, its a roundabout way of asking: How much can you tolerate yourself?)
My answer:
I think I could probably remember enough of myself to understand my alt-self enough to become friends. But if their timeline got fucked up, and their parents die, I’m not sure I can actually deal with this kid who, is me, but not me, like… I would probably get so annoyed at this kid, but also, I’d think about myself when I was 10, when I was this kid, and then feel pity. Idk if I could ever abandon an alt-self, because I’ve already feel abandoned (not literally, but like as in terms of the emotional side of parental love that I never gotten), I wouldn’t wanna see someone who is practically me, also go though the same abandonment.
Idk… Time travel is so weird.
Not sure your scenario is really about being friends. Choosing to take care of a child is more about my situation, than how much I might like them. If you are only taking care of a child because you like them, you are putting them at a lot of risk. Even great kids will be challenging, and a decent person cares for them even when they are unlikable or downright awful. That’s pretty much the definition of unconditional love (though, reading through the comments here it sounds like a lot of lemmings didn’t get that growing up).
As for, would I like myself? 10 year old me, sure! We share a lot of interests (I’d love to dm a game of dnd for him), and although a kid can be quite annoying, I think I’d be pretty fond of the little fella. I suspect I’d also gain a lot sympathy for my parents, and would love to try supporting him with some of his creative projects that he was always starting and never finishing.
20 year old me? Probably too wild to be close friends and I’d think he was an arrogant idiot at times, but probably find him kinda hot so I’d let it slide (my ‘type’ is pretty much younger me…). 30 year old me? Not all that different, could definitely be friends!