Does the lack of は change the sentence?


So I saw this sentence: `きのう初めておすしをたべました。` And wondered if the は is just being
left out. Does the sentence change any if は is added in? Like so:
`きのうは初めておすしをたべました。`




I think this は is a "topical は" or "contrastive は". 昨日初めてお寿司を食べました sounds to
me like you're just reporting that you ate sushi for the first time the day
before, and 昨日"は"初めてお寿司を食べました sounds to me like "Speaking of yesterday, I ate
sushi for the first time," (probably someone's just asked what you did
yesterday, like 昨日、どこに行ったの? or 昨日、京都で何したの？etc.), or "(The day before yesterday
I went to eat sukiyaki, and) as for yesterday, I ate sushi for the first
time".

