Assalamoalaykom W.W. My question is, is it bid'a to celebrate n graduation day? and to give a gift to someone who graduated?
Bidaa in Islam isn't always a bed thing. Things such as Tarawih salah, compiling the quran, and other things are good bidahs ( bidah hasanah). Anyways to your question.
It shouldn't be bad to celebrate it, so long as it is in a halal setting (not mixed genders, no alchohol or questionable things etc...) Based on the way you asked, i sense this is not a problem, moving on. Like anything, all actions are on the intentions, if the graduation is to raise your status and feel proud, then no. If it is a happy setting in which you exchange greeting and gifts with others in a way that strengthens your brotherhood then by all means host one. I graduated high School last year, and we had a very nice open house, and we even invited our none Muslim friends and neighbors, which also helps in dawa. The prophet would always give off donations, but would always accept gifts, love for your brother what you love for yourself.
I hope this help, salamwalaykum.
I don't think its a Bid'a .
Your intention behind giving gift is important. What I mean by "Intention" is that, you can give a gift to friends of your gender (if you don't have any wrong feelings for them), but if you give a gift to any opposite gender then it will open doors for shaitan, because then you will increase his/her confidence to interact with you or give him/her any kind a message that you are ready to make him/her your friend or you yourself want him/her to become your friend and you wanted to start a conversation with him/her.
Narrated 'Umar bin Al-Khattab (R.A):
I heard Allah's Apostle (S.A.W) saying, "The reward of deeds depends upon the intentions and every person will get the reward according to what he has intended. So whoever emigrated for worldly benefits or for a woman to marry, his emigration was for what he emigrated for."
Sahih Bukhari, Volume 1, Book 1, Number 1
Note: I am not saying that you asked this question regarding giving gift to opposite gender, but as you have not mentioned to whom you want to give gift or what kind of gift so I gave you a detailed answer, the best of my knowledge.
Lastly, tomorrow is 14th February so you should not give any kind a gift to anyone tomorrow which could raise any kind a doubt.