Wa'alaikum assalam! Keputihan brown sikit tu boleh normal, tapi depends on context lah, ada kemungkinan ia spotting before period, or sometimes it's hormonal changes especially kalau baru habis haid. A few of my mum friends experienced the same thing and it turned out fine, tapi since you're asking, I'd suggest check with your doctor or gynae just to be safe, especially kalau it comes with other symptoms like itching, bau aneh, or sakit perut. Better to know for sure kan, daripada worry sendiri!