replying to OP, it is an achievement that's sure, an *achievement* can simply be a goal set by yourself, I consider each new 100 rating points (Like if I reach 1500 blitz I will consider this) I consider as an achievement so yeah!
is getting to 1200 even considered an accomplishment?

If you enjoy chess for chess sake, then the rating shouldn't matter. However, when starting out achieving 1200 is absolutely an accomplishment of which you should be proud.
Anyone wishing to advance that is below 1200 will certainly think it is an accomplishment that they one day hope to achieve. Those above 1200 may think less of it, but they too at one time had to work to achieve it, too. So yes, any way you choose to look at it, 1200 is an accomplishment. Well done!

I find this funny since I was stuck at 800 elo for five years T_T

For a beginner who started out recently and made progress to reach 1200 – that is an accomplishment.
Reaching 1200 because it is chess.com's default starting rating – that is not.
Reaching 1200 when you started at chess.com's default rating of 2000 – that is something to feel ashamed of.

Reaching 1200 when you started at chess.com's default rating of 2000 – that is something to feel ashamed of.
lol people who think they're gud and select "expert" when making their account-

Thats happening to me right now.

If you go from 900 to 1200, yes, that's an accomplishment for you, but it's unlikely that anyone else is going to care. There are GMs who dwell in obscurity and would probably be thrashed by Magnus Carlsen if they played him. Bottom line is: Don't care about whether you are better than others, just enjoy playing Chess.

This is a really good improvement - it's an average of 100 per month. Getting higher in chess simply takes patience and practice. for example, when I was pushing up to my current online rating, my progress was very jagged (and has a rate of increase lower than yours overall)

everything you work hard for and which pays off, is an achievment
and elo improvement over time cant be meassured that easily in my opponion. For example, if you learn alot of new things, which only need to be applied in certain positions (basic tactical pattern or basic theoretical endgames , some little opening prep) which result in a huge leap, than 300 in 3 months isnt that special. But if you only checked masters games, and reviewed your games and worked on your gameplay (without working on concrete stuff), than 300 points in 3 months is truly amazing
edit: Ahh btw in the end it doesnt matter if it was the first or the second case I mentioned. Your gameplay went uphill by alot
Reaching 1200 is definitely an accomplishment! I am pretty sure it was Ed Coan (one of the best powerlifters the USA has had) who was asked what it felt like to squat 1000lbs. He asked the person asking the question what their max squat was. I forget what they said but lets assume the questioner said 400lbs was his max. Ed Coan then asked him what it felt like to squat that 400lbs and the questioner answered saying something like, "it felt like squatting a car" (i forget exactly what he said). Ed Coan responded saying, "thats how it feels to squat 1000lbs."
The point is that strength is relative. A 900 reaching 1200 is huge progress. Keep grinding!