Translation:I will not understand the lecture but I will go.
Shouldn't this say "... ach rachaidh mé ann." ? I remember that if you say "I am going" you can't just say "Tá mé ag dul", you have to say "Tá mé ag dul ann."
In an Irish instruction book that I have called "Speak Irish Now", in Lesson 41 it says this:
"When you're saying that someone 'is going', you usually say where they're going. In English, we'll often leave the place we're talking about implied. In Irish, a word for the place is always included, even if it's only the vague 'there,' 'ann'."
It gives examples like: An bhfuil sé ag dul ann? = Is he going?. Níl mise ag dul ann. = I'm not going. Etc.