Yes, it is OK to wear just a bralette. However, depending on the size and weight of your chest, you may not be comfortable wearing only a bralette as they do not typically include support features or offer much modesty. Also, if you have a heavier chest, a bralette will not be able to reduce bouncing, which can contribute to sagging in the long-term.
Shop Honeylove Bras
CrossOver Bra Wireless Bra
Honeylove's criss-cross mesh adds a signature touch, and a bonded underbust lifts without underwire. A wide wing with back-smoothing fabric eliminates back bulges. Adjustable straps and back let you modify your fit, and the straps can also be crisscrossed to stay hidden under racerback tank tops.
3D printed velvet adds support, and a bonded underbust lifts without underwire. Adjustable straps and back closure let you modify your fit. Straps can also be crisscrossed to stay hidden under racerback tank tops.