Made books for both my kids, want to write in the front cover but have no idea what, help please!

Ok so its a sort of scrapebook where each page will have a different school year. Each year i will do a short interview with them and ask them questions such as "what was the best thing you did this year?" or "who was your best friend this year?" "favorite class?" "favorite tv show?" and ill write the answers down on the left. Then on the right beside it i will include pictures from everything they did that year (well not all, but the highlights). I custom made the books for both kids and they're really nice. Hardcover and everything. Not cheap at all...I even got started on my son's pre-k entry since this school year is almost over. I wrote down his answers to the questions i asked him and am adding pictures of him with his class, him at baseball practice etc. I know im rambling on i apologize i wanted everyone to get a good idea of the type of book i did. I should also mention that i don't plan on showing either or my kids these books until they turn 18, then i will give it to them as a graduation gift.Anyways...someone suggested that i should write a small something on both front inside covers for them to see. Something thoughtful. But thing is, i'm just kind of stumped. I have no idea whether i should get gushy or just keep it light and funny for them. Can anyone just give me anything, thoughts suggestions etc for me? via /r/Parenting http://ift.tt/2pGyFbq