e4 or d4

it doesn't matter. i personally prefer 1.d4

1.e4 is best by test! no other first move does as much good. It opens lines for the Queen and the Bishop both, you gain control of d5, and f5. there are plenty of other good first moves, but 1. e4 is best

The toughest part of developing an opening repertoire is choosing a reply to 1. e4.  This holds true from the novice level all the way up to the Super GM level.  1.d4, and the flank openings are perfectly fine, but, as a rule, they just don't require as much precision or risk-taking from the Black player.

If you neglect having 1.e4 openings in your white arsenal, then you are giving your opponents a break.

 Chess engines usually show a slightly higher score for d4, probably because the queen protects the pawn. Fischer had an influence on chess to choose one opening and stick with it, namely e4.  Yet with World Champions like Magnus Carlsen, he takes quite the opposite approach to chess, playing a wide array of openings, making him hard to prepare against as you don't even know what opening to prepare. With all this in mind, I tend toward d4. The queen's gambit you can win the pawn back instantly, or you can play something else like develop your knight. I could care less about my opening, as I usually out-tactic my opponent. But when I want to play a really strong game, I go for d4.

No move is "better" e4 is usually more aggressive while d4 is usually more positional. c4 and Nf3 tank whites advantage and are all about outplaying your opponent in the middle game. I personally prefer d4 because I have a positional stile.   

your making sound like e4 is perfect in every way. have you heard of the sicilian? a brilliant defence black can play in reply to e4. an e4 player needs to prepare for this otherwise that player will get destroyed. this is one of the reasons some people play d4. (not the only reason but a minor reason which can impact that decision.) e4's good but not perfect. d4 is also good but not perfect.

Neither is better. This question is asked a lot. Try playing around with both and see what you like. Also you can try to look up some of the resulting theory and see which sorts of positions you think you would prefer

the Sicilian is a respectable reply to 1. e4, but in all fairness both sides will still have plenty of wiggle room for dynamic play. you are forced to play chess, so whoever is better will win

"... For players with very limited experience, I recommend using openings in which the play can be clarified at an early stage, often with a degree of simplification. To accomplish this safely will take a little study, because you will have to get used to playing wiith open lines for both sides' pieces, but you can't eliminate risk entirely in the opening anyway. ... teachers all over the world suggest that inexperienced players begin with 1 e4. ... You will undoubtedly see the reply 1 ... e5 most often when playing at or near a beginner's level, ... After 2 Nf3, 2 ... Nc6 will occur in the bulk of your games. ... I recommend taking up the classical and instructive move 3 Bc4 at an early stage. Then, against 3 ... Bc5, it's thematic to try to establish the ideal centre by 4 c3 and 5 d4; after that, things can get complicated enough that you need to take a look at some theory and learn the basics; ... Of course, you can also play 1 d4 ... A solid and more-or-less universal set-up is 2 Nf3 and 3 Bf4, followed in most cases by 4 e3, 5 Be2 and 6 0-0. I'd rather see my students fight their way through open positions instead; however, if you're not getting out of the opening alive after 1 e4, this method of playing 1 d4 deserves consideration. ... a commonly suggested 'easy' repertoire for White with 1 Nf3 and the King's indian Attack ... doesn't lead to an open game or one with a clear plan for White. Furthermore, it encourages mechanical play. Similarly, teachers sometimes recommend the Colle System ..., which can also be played too automatically, and usually doesn't lead to an open position. For true beginners, the King's Indian Attack and Colle System have the benefit of offering a safe position that nearly guarantees passage to some kind of playable middlegame; they may be a reasonable alternative if other openings are too intimidating. But having gained even a small amount of experience, you really should switch to more open and less automatic play." - IM John Watson in a section of his 2010 book, Mastering the Chess Openings, Volume 4

Your choice.