すべき is する+べき. べき basically means should
.
記念すべき日 is then 記念する + べき + 日 and means as you surmised, a day that should be celebrated
or a day we should celebrate
.
The main action is 感極まる思いであります, which is basically a fancy way of saying extremely emotional. Why does the speaker feel so emotional? The に tells you that この記念すべき日を迎える事ができた事 is what the speaker feels so emotional towards.
I think the important thing about the rest of the sentence is that all the 事s act as nominalizers. 迎える means something like to arrive at this day (It's definition 4 on デジタル大辞泉).
この記念すべき日 = This day that should be celebrated
[この記念すべき日]を迎える = Arrive at this day that should be celebrated
[この記念すべき日を迎える事]ができた = We are able to arrive at this day that
should be celebrated (事 makes the previous phrase a noun phrase)
[この記念すべき日を迎える事ができた]事 = The fact that we are able to arrive at
this day that should be celebrated (事 makes the previous phrase a
noun phrase)
So then the speaker is saying that:
today I am extremely emotional at being able to arrive at this day
that should be celebrated.
Honestly that just sounds pretty bad in English.