How soon is too soon to start dating after a breakup? [22f with my ex 22m]

I just got out of a one and a half year relationship with my boyfriend, a little over a week ago.

Things had been going south for about 7 months. I was always just waiting and hoping for things to get better, for him to value me more or stop ditching me on weekends, etc. We rarely saw each other even though we live right down the street from one another and go to the same college, we only spent about one night a week together. I always made excuses for him, like "oh, it's just because we're both really busy and stressed with school".

Well semester ended in the spring and summer cam into play. I was really excited because my boyfriend was staying in town this time (we did long distance last summer). I thought that we'd see a lot of each other because there were no major obligations other than our jobs, which started at the same time anyway and were not particularly exhausting.

I was wrong.. I saw him a bit more.. maybe two times per week.. maybe weekends.. but really not enough. Not nearly as much as I had expected. I spent so much, over seven months of this relationship, feeling disappointed and left behind. So I ended it. He seemed very sad about my decision, but agreed it was for the best since we don't know where we will wind up when we graduate. We're on good terms, but we aren't speaking (I don't want to, he really hurt me).

So now I have jumped back into the dating pool. For whatever reason in just a little over a week alone, I've had five guys ask me out. Not on tinder, but in person, not at a party, but in broad daylight just out and about. And I've said YES! Because gosh, I haven't been on a real date in so long, my ex and I never did that.

So the reason that I'm asking this question is because one of my good friends is actually mad at me for moving on so fast. She said that I should consider my exes feelings and wait it out for a little while. This doesn't make any sense to me. I've been waiting around for so long and I finally don't have to wait anymore. While I care about my ex, and I don't want to hurt him, we are not married, we are no longer dating, why should I sit around and wallow in sadness when I can just move on. Is there some sort of unspoken rule of how long you're supposed to focus on being sad? I don't like sitting alone and being miserable. I don't like that people expect me to be absolutely shattered. I'm not. I do miss him, but I know that this is for the best. I'm not rebounding, I'm not getting back into a serious long term relationship, and I am not being reckless.

I'm just single, and some very interesting and funny guys would like to take me out on dates. Is it wrong for me to go and continue my life and be happy?

tl;dr: I just got out of a serious long term relationship a little over a week ago. My friend is mad that I've started going on dates again so soon. Is it wrong for me to try to move on?