Ayyy normal je sayang, especially for first pregnancy! The hormones (relaxin) start relaxing your ligaments from early on, and your body is already preparing even though baby is still so tiny, a few of us had backache quite early too. But since you're in the first trimester, best to check with your doctor just to make sure it's nothing else and get their advice on safe ways to manage it, okay? In the meantime, try not to carry heavy things and rest when you can. Hang in there, you've got this!