Translation:I eat dinner at 5 P.M.
In online video games I've seen Japanese speaking players use 555 to mean go go go.
Oh Japan, with their silly syllables. They're so much easier in English, there'd no issue understanding their syllable sounds if they were more like they are in English. If only there were some way writing their intent with different Kanji would mean they're able to convey more context when their syllables sound similar.
Although some people think that because in the morning, 朝 (asa), we eat 朝ご飯, and in the afternoon, 昼 (hiru), we eat 昼ご飯, then at night, 夜 (yoru), we ought to be eating 夜ご飯. However, the word 夜ご飯 didn't initially exist in Japanese. Someone just made that word up recently, so that the term 夕飯 (yuuhan) is generally applied.
Here, in Brazil, we would never eat dinner at 5pm. we use to dinner at around 20h to 21h in the evening.
At 5pm we use to have a cofee-break, mostly with family, and eat breakfast stuff, such as cookies, coffee, milk, breads, butter and jelly.
Also, we consider 5 pm as noon, not night. =]
There are all sorts of variations in what English speakers call various meals - in Australia, a hot meal eaten at lunchtime would be called dinner and our evening meal is often called tea, and it would definitely be tea it eaten at 5pm (little old ladies eat at this time and they would not call the evening meal dinner - that's a more modern usage).
This is one of those colloquial things we do in English where we shorten the future tense "I am going to have" into "I am having". You can make an argument for it because it's what people naturally say. But it's easily confused with the present progressive tense (I am currently having dinner), so I think it's better to avoid it. The other problem might be using "have" instead of "eat", though once again it's very natural in English to say "have dinner".
食べます is present/future simple
食べています is progressive
The main difference in usage is that progressive describes the action happening now while present simple is about regular activities. "I'm eating dinner at 17:00" means it's now 17:00 and I'm eating dinner at this moment while "I eat dinner at 17:00" means that my usual dinner time is 17:00.