i'm not as sure as maddie is.
i think it would depend on whether or not your hymen is still intact.
i believe that an intact hymen is the true measure of a virgin, not whether or not there has been any sort of entry into the vagina. while in 90% of cases those are mutually exclusive events, meaning that if a penis enters a vagina, chances are there is not an intact hymen, there really wasn't enough information about how far the penis entered the vagina to make the determination. for all we know, it could have just barely touched the entrance, which caused enough pain to get you to make him stop.
so, in my mind, if you still have an intact hymen, you are still a virgin. if you do not have an intact hymen, you aren't.
the problem i have is "why does this matter"? if you didn't have a problem with him attempting to put his penis inside you, then why do you have regrets about it now? why is it important to you to still be a virgin? what makes you think that the next time you get "excited" that you won't succumb at that time again?
i think you need to do some "soul searching" and really figure out what you want to do and why you want that.
there's nothing wrong with being a virgin and remaining one. i am not a virgin, but that's another story altogether.
jasmine