Condom and ED

Guys I am 26 year old I have been watching porn for the last 7 or 8 years now but i was not an addict at least i think so. The thing is that i get aroused by my gf when she is near me or when we talk over phone even when the talks are not sexual but recently we tried to have sex as we both are virgins .on two occasions everything was ok at the beginning I had firm erection until foreplay, and then we tried penetration i tried to wear condom the head of my penis wont go inside the condom how much i tried and right then and there i lost erection and it would not get up, add to that it is not everyday we get the chance to have sex so there was the added pressure but still i should have got hard the whole time i was semi hard. Guys is this ED ? What should I do to prevent this next time ? This is the prime reason of me not doing PMO.

 

Thank you for the answer @StopTheMusic