"У мене є бабуся."
Translation:I have a grandmother.
In Polish we use that construct ("у мене є") as well, but often it means "there is ... at my place (where I am)", so "U mnie jest babcia" would mean "My grandma is at my place (presumably home)". Is there a context where "у мене є" would mean the same in Ukrainian? If not, do you have any equivalent?
Ukrainian doesn't really use articles (the/a/an), but English does. An article is necessary in English here, but there are circumstances where an article is not required, e.g. "I have grandparents" (plural noun) or "I have courage" (abstract noun). However! Even these circumstance /can/ have articles; it just changes the meaning, e.g. "I have the grandparents" refers to some specific grandparents relevant to the conversation rather than stating a fact about your biological grandparents. For that matter, "I have the courage (to do something)" means that you have /sufficient/ courage rather than some unspecified quantity of courage.
It can get complicated, but I'm sure if you search for it online, you can find some good resources (https://owl.english.purdue.edu/owl/resource/540/1/)
You could get away with that in conversational American English; however, it would sound much more natural to contract the first two words: "I've got a grandmother." I'm not sure if it's colloquial though. If it is a colloquial expression, then they probably don't want to encourage it.