日本語

日本語はそんなに難しくないよ！でも、もう(勉強を始めてから)５年も経つのに、まだ僕の日本語は上手/じょうず/じゃない (*1)。おかしいでしょう？

*1: when you have 'I' as a sentence subject, うまくない is fine. The adjective generally descdibes person's ability: 僕は日本語が上手/うま/くない

Not really. 5 yeras is too short for language learning except when the learner stay in the country of the language and have intense training. No need to push yourself, if you're feeling upset. Be patient, and keep working on it. All the best.