The conventional wisdom says rebound relationships are always a mistake — a way of avoiding grief rather than processing it. That's sometimes true. Jumping into a new relationship specifically to prove you're “over it,” or to make an ex jealous, or to fill a silence you're afraid to sit in, usually just delays the real work and puts an unfair burden on the new person, who becomes a distraction rather than a partner.
But not every relationship that starts soon after a breakup is a rebound in the harmful sense. Some people process grief quickly and are genuinely ready to connect again sooner than the arbitrary “wait six months” rule suggests. The real question isn't how much time has passed — it's whether you're seeking a person or seeking a distraction. If you find yourself constantly comparing the new person to your ex, using them primarily to avoid being alone with your thoughts, or unable to describe what you actually like about them beyond “they're not my ex,” that's a sign you're not fully present.
The fairest thing you can do, for yourself and for a new partner, is honesty — with them and with yourself — about where you actually are. A slower start, transparency about your recent breakup, and paying attention to whether you're excited about them specifically, rather than relieved to not be alone, will tell you more than any calendar-based rule.