Is it too late to submit a rec letter?

So, I’ve submitted my application, along with the two teacher recs and a supplemental rec from a summer school teacher. However, my math teacher, who previously did not reply to my email over break asking her to submit my rec, said she would like to submit one on my behalf, if it’s not too late. She knows me a lot better than all my current recommenders, and she is the sponsor of the math team, of which I am the Vice-President. I feel like it would add to my application, but I fear it is too late and would be looked at negatively if I submit something so late and superficially extraneous given I already have all my recs ready.

Thanks!!

MIT is already reading applications, so it is late to be adding another rec letter that is also more than asked for. But will they accept it? Only MIT knows, not this forum.

But the question I have is: Was applying to MIT a last minute decision? Why wait until break to ask for arec lrtter. The request is then by email when it really should have been in person.

@HPuck35 it was a relatively last minute decision, decided to apply in December and close to interview deadline. I emailed my math teacher, who had already written my Common App recommendations for EA, a few days before school closed. I went to see her when she did not respond the last couple of days before school ended, but she had left early for break and only emailed me back on the 31st.

Can I get some advice from @mitchris ?

They are less strict about receiving things late that are not expected to come from the applicant. There is a point when they actually let applicants know if something in their application is missing. And then give you time to get it in to them.