Having had time to reflect on the transfer and absorb all the reaction, with person after person offering pats on the back and talking about how he is destined for such great things, I am more inclined to say "Whoa!".
I just worry that this is already getting a little out of hand. No-one is more delighted than me for Ryan and I hope he goes on to be a tremendous success as I believe he has so much talent.
We are in fantasyland with him right now, though. There has to be a little reality introduced to the discussion about his future. A degree of perspective, if you like.
From the moment Ryan came on to the scene aged 16, it was clear that he was gifted with great technical ability. He is going to the right country in Portugal, because he will be given more time on the ball there within a style of football that is generally a little less physical.
However, he really has to strengthen. I have seen a number of boys with great talent who just don't get stronger as they get older and I hope he does not prove to be one of those.
Allied to talent, you need that power and conditioning. He is quite lightweight and I worry about him developing his physique sufficiently to really be a success at the top level.
The comparisons drawn between him and Lionel Messi, as we all know, have been a little extreme. However, he does ride tackles well and lands running. He has that balance to him.
What he should do is consider what Messi has done to develop his strength to bounce off people, take kicks and go again. Messi is not the tallest player in the world either, but he can more than handle himself on the park against much bigger opponents.
The next couple of years will be hugely important for Ryan. By the time you reach 19 or 20, you are going to be all the man you'll ever be and he needs to work on his physique.
Above all else, I hope Sporting Lisbon have signed him with a view to slowly bringing him through the ranks rather than putting him straight into the first team. They have paid a hefty sum for a player they see as a work in progress, but I just hope they don't demand too much from him straight away.
Of course, the first picture taken in Lisbon after the deal was concluded saw him shaking the hand of club president Bruno de Carvalho between huge photographs of Cristiano Ronaldo and Luis Figo. That raises expectations in itself.
Does he have a talent like Ronaldo or Figo's? I am not sure.
Does he have superstar potential? When I look at what Gareth Bale was doing aged 17 at Southampton, before earning a £7m move to Tottenham Hotspur, I cannot say Gauld has matched that thus far.
I'm sorry for dampening everyone's enthusiasm, but what I saw in the closing months of last season makes me worry about the boy.
He started like a whirlwind and produced some marvellous performances. I have spoken to Mark Wilson at United about Ryan and he raves about him, claims he is one of the best players he has seen at that stage of his development.
However, I studied him towards the end of last season and I wasn't really seeing progress. When I go back to when I was a young player, coming up to Dundee at 19 after spending time at Chelsea, I recall how hard that second season of playing regularly at first-team level was.
People get to know what your strengths and weaknesses are. They develop ways to play against you. I think Ryan encountered that during the second half of last term and I am not sure he handled it. People got to know his game and closed down the space he was enjoying.
What he has to do in response to that is come up with new ways to make space for himself and he found difficulties in that.
He was listed on the substitutes' bench for the Scottish Cup final loss to St Johnstone and couldn't even be termed a first-team regular at United towards the end.
But where I don't see any problem for Ryan is in coping with moving to another country and dealing with the expectation levels. I was 16 when I moved to London to play with Chelsea and I would say that he will definitely have a degree of homesickness to deal with.
However, things have changed a lot since my day. I travelled on the train because I couldn't afford to take flights back up the road. Nowadays, travel is much easier and modern technology makes it infinitely easier to stay in regular touch with everyone back home.
Sporting Lisbon will do everything they can to help Ryan settle and I hope he can have family and friends over there with him for the early months at least.
You deal with that side of things as a top-level player, but I know he is a lovely, level-headed lad and you don't get many like him.
I have seen a number of boys in my time in the game who never grasped the realities of life. Some players get their big move and become prima donnas and unpleasant people, but Ryan is never going to let all that get to him.
Chances are that he is already made for life. I just hope he does go on to become a superstar and convince someone to invoke that £48m clause.
Go on, Ryan. Prove my reservations wrong. Whatever you may think of this column, I wish you all the very best.