How the bike fits matters a lot. If you have outgrown your current bike, you really will benefit from having a bike that fits you well, in both comfort and efficiency (=speed). If you can simply raise your saddle and still maintain an efficient and comfortable position on your current bike, then no problem. If you have grown in the torso as well as the legs, you might be able to put a longer stem on the bike to accommodate the change.

Weight? Not as big of an issue, especially if spending money is an issue. Where you will notice weight the most, in terms of speed, are in the areas you are fighting that weight with every pedal stroke, i.e., rotating weight = wheels/tires, cranks, your bottom bracket.

Components: if your components work as you like them to, no major cause to upgrade. More expensive components work a bit better, and weigh a bit lighter. Again, it is the components that rotate as you ride that matter the most, and where you should focus your attention and $$ when considering an upgrade.