"I became pleased." or "I am pleased.", but that is the literal and not the way the sentiment is described in English. http://www.turkishdictionary.net/?word=oldum http://www.turkishdictionary.net/?word=+memnun http://www.turkishdictionary.net/?word=olmak
You could think of it as "Pleased to meet you" or "It's my pleasure." The sentence above is "Nice to meet you" and I don't know if these versions are also correct to Duolingo.
This exact question was answered 3 years ago, right in this same "discussion" …you can scroll and read: "Meet" and "see" have different meanings. I meet you for the first time. After that I see you. "Nice to meet you" indicates that you are speaking to someone new. "Nice to see you" indicates that you are speaking to someone you already know.