If you are wondering if losing your virginity will lead to feelings, and in general, I would say the answer is probably. Commonly. Not necessarily but often.
People don't necessarily feel in love after sex, but if the sex is good and you keep doing it thinking you're in love, well, every romantic relationship that's ongoing has the stage of love-feelings called "limerance." You can look this up. The longest that usually lasts is 2 years. The brain fMRIs light up like you're on crack. Literally addicted to someone. But that's romantic love, which a sexual encounter may or may not be a part of or lead to.
I wouldn't just say it, it's sort of an idealistic thing to say "say you love them when you feel it" but when did life play out like the Notebook for reals?
The poster above with when their happiness was equal to your own wasn't off the mark. It's hard to know when it's them or the hormones, 4 months is a reasonable timeframe to think you know someone beyond the superficial, I dunno.
Say it when you feel it, and you think they won't run because you said it, which is usually when they're as invested as you are. A lot of love columns I read suggest that a relationship is in its best place when you're both showing ACTIONS showing similar actual investment in the relationship. You might think you love someone, but if their actions are showing they're maybe just not as excited about this as you are, I would just watch my step.
