5000? I have close to 8000 in japanese and I consider myself still a beginner.
Native is at least 20000-25000.
As long as you are continuing to learn then 5000 is a nice start, but you are not going to read novels and speak about broad topics with that vocabulary.
Are we talking about vocabulary usage or recognition? Estimates vary, but the rough consensus for English seems to be that the educated native speaker recognizes around 15,000-25,000 words, but only uses around 5,000-8,000 in their own speech/writing.
The average vocabulary of the average person in their NATIVE TONGUE is just over 3500 words (it varies a lot from culture to culture).
The average vocabulary of a University Graduate in the Arts is 10-12000 words. In the sciences it varies greatly, chemistry, biology and medicine being the most demanding at >15,000.
Someone with a vocabulary of 20-25000 words would be highly educated or very well read, or an specialist in a field.
If you have a Japanese vocabulary of 8000 words, you already have a bigger vocabulary than 74.13% of the population (if you understand what that percentage represents, you already have a larger vocabulary than the majority of people).
I don't know where you got that idea from, but I took an online test for English (which is my native language) vocabulary, and found that I knew about 30000 words. And I wouldn't consider myself to be that unusual.
Native is at least 20000-25000.
As long as you are continuing to learn then 5000 is a nice start, but you are not going to read novels and speak about broad topics with that vocabulary.