“老鹿蹒跚”是“小鹿乱撞”的一个衍生词（yǎnshēngcí. Derivative word）。
老（lǎo）old
小（xiǎo）small, young
鹿（lù）dear
蹒跚（pánshān）stumble, walk in an unstable and slow motion
乱（luàn）random, disorder
撞（zhuàng）hit, bump in
官方（guānfāng. Official source）对这个词是这么解释的：指部分90后的叔叔阿姨看到喜欢的人后的心理活动。不同于少男少女（shàonánshàonǚ. Young boys and young girls）恋爱时的小鹿乱撞，这些叔叔阿姨们在经历一段又一段恋爱后对爱情的渴望并没有那么强烈，来了就来了，不来也罢。
The official translation for this phrase is: refers to the psychological activity of those uncles and aunties who are born in the 90s when they see someone they like. Unlike teenagers whose heart will just pound, these uncles and aunties do not have desires for love as strong after multiple romantic relationships. When love comes they just accept it, if it does not come then who cares?
90后的叔叔阿姨？有没有搞错（gǎocuò. Make a mistake）！
Born in the 90s, uncles, and aunties? Are you serious?
放开称呼不谈，“老鹿蹒跚”这个词会适用于（shìyòngyú. Applies to）所有的90后吗？
Leaving out the form of address, does ‘old dear stumbles’ really apply to everyone born in the 90s?
官方解释中有一个很重要的条件，那就是：“经历了一段又一段的恋爱”。不知不觉中，这一类人对于爱情的看法就淡了，甚至有可能会有些抗拒（kàngjù. Resist, resistance），就如同老鹿蹒跚一样。就算遇见了很喜欢的人，也心有余而力不足（xīnyǒuyúérlìbùzú. The heart has extra but power is not enough; think of something but just do not have the energy to do it），不会去很猛烈地追了。
This is one important requirement in the official definition, which is ‘been through multiple romantic relationships’. Before they know it, these people do not feel about love as strong as before, may even begin to repel its notion, like an old dear. Even if they meet someone they really like, they may not have the energy to make a move.
但是也有一部分90后，可能没有很丰富的感情经历。他们可能在遇见喜欢的人时，依旧会心里小鹿乱撞。勇往直前（yǒngwǎngzhíqián. Be brave and go straight forward），想追就追。
There are also 90s’ people who may not have a lot of romantic experiences. They may still feel their heart pounding like a young deer when they meet someone they like. Just go at it without any fear.
同作为90后的我，其实上述两种类型都不属于。为什么呢？因为我会脑内恋爱，在心动之后会立刻把对方怎么度过一生都想完了。在这之后，我就不会有恋爱的想法了。
And as a fellow 90s’, I do not belong to either category above. Why? Because I will have a ‘mentallove’, I picture our whole life together after I have a crush. After that, I will not have the thought of falling in love at all.
上面哪一种适用于你呢？不管是哪一种心态，佛系、小心翼翼亦或是充满渴望，在属于我们的爱情真的来了的时候，还是要牢牢地把握住（bǎwòzhù. Hold on tight），不要轻易放手。
Which of the above categories apply to you? No matter which one, Buddhist-like, careful or full of hope, when love really comes knocking on the door, we should just grasp it and do not let it go easily