I can't have 5 stars in GTA V
I only reach 4 stars. Even with mods I cant reach 5 stars.
Have you been a boy scout in the past? Maybe that's why...
No, but seriously - I think that in order to get the highest wanted level in any GTA game, you first need to, kind of, build your reputation as a criminal.
I remember that in GTA 3 and SA it was simply impossible to get the highest wanted level near the beginning of the game, even when fully armed and slaughtering civvies and men in uniform by droves. Only when you used cheats perhaps. This is my experience at least.
Maybe the in-game law enforcers simply do not consider you to be that dangerous a target yet. However, you may try perhaps to intrude some of the off-limits zones around Blaine County (we are speaking GTA V, right?) like military base or Los Santos docks. I just don't remember if LS Docks give you automatic four or five star rating...