At a glance, people must think Altair and JM were lovers. Ah ... they did like each other, but since both of them were still very young, Altair was only 16 years old and JM was 15 years old; they hadn't thought about officially dating.
Their parents had given them lengthy advice over and over again not to think about love and dating at such a young age. Nicolae and Alaric even said their children must wait at least until they are a century old before they could even think about falling in love.
So, of course, Altair and JM always acted like they were just very close friends.
Vega felt that even though neither of them was dating... yet, it wouldn't if she made their schoolmates think Altair already had a girlfriend so they would stop chasing him. Vega was tired of all the confessions from girls and endless fights with other boys. It would only happen if they thought he already had a girlfriend.