See this earlier question about the same matter, where I see you have posted.
uk-tier-4-student-visas/uk-visa-tier-4- ... 83073.html
As long as you are clear that your first stay is a short visit that meets the Standard Visitor rules, it is fine.
The problem comes when someone (nearly always your countrymen for some reason) comes to the UK as a "visitor" before their Tier 4 vignette start date, thinking they can just stay and somehow regenerate into a Tier 4 migrant when their vignette kicks in. Having not entered on their vignette, such a person will not be able to collect their BRP, cannot enrol on their course, and may have used deception on entry.
I do not give immigration advice. I refer you to Immigration Rules, guidance, other online content and to your sponsor.
