Welcome to the disease and the forum we’d all rather not have to belong to.
It seems to me that an MS diagnosis is usually a big shock, even when someone has expected the diagnosis. And if you really weren’t expecting it, then it’s an even more frightening place to be.
Have a look at https://www.mstrust.org.uk/understanding-ms/newly-diagnosed-multiple-sclerosis The MS Trust have a lot of excellent resources (as does this site of course). Researching your new diagnosis is one way to try and get a handle on it and in some small ways to ‘tame’ the beast.
I would imagine that in the first instance at least, you’ll be diagnosed with relapsing remitting MS. This is where you have relapses, or ‘flare ups’ of symptoms which might be treated with steroids to help shorten the relapse. A relapse would then be followed by a slow remission, either fully or partially, over weeks or months.
Disease Modifying Drugs (DMDs) are available, these aim to reduce the number and severity of relapses. There are many different DMDs, each has an expected average relapse reduction rate, but each drug also has the potential for side effects. See https://www.mstrust.org.uk/understanding-ms/ms-symptoms-and-treatments/ms-decisions/decision-aid for some info about the drugs available. When you are assigned an MS nurse s/he will guide you through what options are open to you (depending on local prescribing centres as well as the perceived severity of your MS).
And as for ‘accepting’ the diagnosis, that’s not essential. It doesn’t matter whether you accept it or not, the bugger is here. Personally, I don’t feel rolling out the metaphorical welcome mat is necessary. Neither do I think acceptance is required. Stamping your feet, getting angry and feeling a good amount of, ‘it’s not bloody fair’ is perfectly normal.
I hope you stick around. Ask all the questions you want answers to. (Relating to MS maybe - we’re not complete know-alls!) We’ll try to help.